Examples with solutions for Multiplication and Division of Signed Mumbers: Substituting parameters

Exercise #1

−a⋅b= -a\cdot b=

Replace and calculate if a=−3, b=5 a=-3\text{, }b=5

Video Solution

Step-by-Step Solution

First, we replace the data in the exercise

-(-3)*5 = 

To better understand the minus sign multiplied at the beginning, we will write it like this:

-1*-3*5 = 

Now we see that we have an exercise that is all multiplication,

We will solve according to the order of arithmetic operations, from left to right:

-1*-3 = 3

3*5 = 15

Answer

15 15

Exercise #2

Solve the following expression:

2a+b= 2a+b=

If a=10,b=−3 a=10,b=-3

Video Solution

Step-by-Step Solution

Let's place the numbers in the formula:

2×10+(−3)= 2\times10+(-3)=

Let's remember the rule:

+(−x)=−x +(-x)=-x

Let's write the exercise in the appropriate form:

2×10−3= 2\times10-3=

Let's solve the multiplication exercise:

2×10=20 2\times10=20

Now we get the exercise:

20−3= 20-3=

Therefore, the answer is:

17 17

Answer

17 17

Exercise #3

a⋅b+b= a\cdot b+b=

Solve the following problem if:

a=−3,b=−2 a=-3,b=-2

Video Solution

Step-by-Step Solution

Let's substitute the numbers into the formula:

−3×(−2)+(−2)= -3\times(-2)+(-2)=

Remember the rule:

(−x)×(−x)=+x (-x)\times(-x)=+x

First, let's solve the multiplication problem:

−3×−2=6 -3\times-2=6

We obtain the following expression:

6+(−2)= 6+(-2)=

Let's remember the rule:

+(−x)=−x +(-x)=-x

Let's write the expression in the appropriate form:

6−2= 6-2=

Therefore, the answer is:

4 4

Answer

4 4

Exercise #4

Solve the following expression:

−a⋅(b+2)= -a\cdot(b+2)=

If a=−5, b=6 a=-5,\text{ }b=6

Video Solution

Step-by-Step Solution

Let's substitute the numbers into the formula:

−(−5)×(6+2)= -(-5)\times(6+2)=

Let's remember the rule:

−(−x)=+x -(-x)=+x

Let's write the exercise in the appropriate form:

5×(6+2)= 5\times(6+2)=

Let's solve the expression in parentheses:

6+2=8 6+2=8

We obtain the following exercise:

5×8= 5\times8=

Therefore, the answer is:

40 40

Answer

40 40

Exercise #5

Observe the following algebraic expression:

a:(−b):c a:(-b):c

Insert the given values and calculate accordingly

  1. a=3, b=−9, c=2 a=3,\text{ }b=-9,\text{ }c=2

  2. a=−4, b=16, c=3 a=-4,\text{ }b=16,\text{ }c=3

Video Solution

Step-by-Step Solution

Let's start with the first option.

Insert the given values into the expression:

3:(−(−9)):2= 3:(-(-9)):2=

First, solve what's inside of the parentheses, maintaining the appropriate sign given that a minus multiplied by a minus equals a plus:

3:9:2= 3:9:2=

Solve the exercise from left to right.

Write the division as a simple fraction:

39:2= \frac{3}{9}:2=

Break down 9 into a multiplication problem:

33×3:2= \frac{3}{3\times3}:2=

Reduce the 3 in both the numerator and the denominator:

13:2= \frac{1}{3}:2=

Convert the division to a multiplication, remembering to switch between the numerator and denominator accordingly:

13:21=13×12=13×2=16 \frac{1}{3}:\frac{2}{1}=\frac{1}{3}\times\frac{1}{2}=\frac{1}{3\times2}=\frac{1}{6}

Let's continue with the second option.

Substitute the given values into the expression:

−4:(−16):3= -4:(-16):3=

Solve the exercise from left to right, writing the division as a simple fraction:

−4−16:3= \frac{-4}{-16}:3=

Note that we are dividing two negative numbers, hence the result must be a positive number:

416:3= \frac{4}{16}:3=

Break down 16 into a multiplication problem:

44×4:3= \frac{4}{4\times4}:3=

Let's reduce the 4 in both the numerator and denominator and we obtain the following:

14:3= \frac{1}{4}:3=

Convert the division to a multiplication, remembering to switch between the numerator and denominator:

14:3=14:31=14×13=14×3=112 \frac{1}{4}:3=\frac{1}{4}:\frac{3}{1}=\frac{1}{4}\times\frac{1}{3}=\frac{1}{4\times3}=\frac{1}{12}

Therefore, the final answer is:

1=16,2=112 1=\frac{1}{6},2=\frac{1}{12}

Answer

1=+16,2=+112 1=+\frac{1}{6},2=+\frac{1}{12}

Exercise #6

Look at the expression below:

−2m:(m+8):1m -2m:(m+8):\frac{1}{m}

Substitue and calculate:

m=1 m=1

m=−1 m=-1

Video Solution

Step-by-Step Solution

Let's start with the first option.

Let's substitute the data in the expression:

−2×(1):(1+8):11= -2\times(1):(1+8):\frac{1}{1}=

We'll solve the multiplication (a negative number multiplied by a positive number gives a negative result), then solve what's in parentheses, and finally the simple fraction:

−2:9:1= -2:9:1=

We'll solve from left to right.

Let's write the division as a simple fraction:

−29:1=−29 -\frac{2}{9}:1=-\frac{2}{9}

Let's continue with the second option.

Let's substitute the data in the expression:

−2×(−1):(−1+8):1−1= -2\times(-1):(-1+8):\frac{1}{-1}=

First, we'll solve the multiplication (we're multiplying two negative numbers so the result will be positive), then the parentheses, and finally the fraction (we're dividing a positive number by a negative number so the result will be negative):

2:7:−1= 2:7:-1=

We'll solve from left to right, let's write the division as a simple fraction:

+27:(−1)= +\frac{2}{7}:(-1)=

Since we're dividing a positive number by a negative number, the result must be negative:

−27 -\frac{2}{7}

Therefore, the final answer is:

1=−29,2=−27 1=-\frac{2}{9},2=-\frac{2}{7}

Answer

−27,−29 -\frac{2}{7},-\frac{2}{9}

Exercise #7

−ab -\frac{a}{b}

Substitute the following into the expression above and solve.

  1. b=−4,a=8 b=-4,a=8

  2. b=4,a=−8 b=4,a=-8

Video Solution

Step-by-Step Solution

Let's start with the first option.

Let's substitute the data into the expression:

−8−4= -\frac{8}{-4}=

First, we can see that in the fraction we are dividing a positive number by a negative number, therefore the result will be negative:

−×−84= -\times-\frac{8}{4}=

Now we can see that we have a multiplication between two negative numbers and therefore the result must be positive:

+84=2 +\frac{8}{4}=2

Let's continue with the second option.

Let's substitute the data into the expression:

−−84= -\frac{-8}{4}=

First, we can see that in the fraction we are dividing a positive number by a negative number, therefore the result will be negative:

−×−84= -\times-\frac{8}{4}=

Now we can see that we have a multiplication between two negative numbers and therefore the result must be positive:

+84=2 +\frac{8}{4}=2

Therefore the final answer is:

1,2=+2 1,2=+2

Answer

1,2=+2 1,2=+2

Exercise #8

In front of you an algebraic expression:

0:−mb+c 0:-\frac{m}{b}+c

Replace and calculate

  1. m=3,b=409,c=8 m=3,b=409,c=8

  2. m=−1205,b=−7,c=3004 m=-\frac{1}{205},b=-7,c=3004

Video Solution

Step-by-Step Solution

Let's start with the first option.

Let's substitute the given data into the expression:

0:−3409+8= 0:-\frac{3}{409}+8=

We'll solve the exercise from left to right, noting that we are first dividing by zero.

Let's remember the rule:

0a=0 \frac{0}{a}=0

In other words, any number divided by zero will equal zero, therefore:

0−3409=0 \frac{0}{-\frac{3}{409}}=0

Now we got the exercise:

0+8=8 0+8=8

Let's continue with the second option.

Let's substitute the given data into the expression:

0:−−1205−7+3004= 0:-\frac{-\frac{1}{205}}{-7}+3004=

As we can see, just like in the first option, we are first dividing by zero.

Any number divided by zero will equal zero, therefore we got the exercise:

0+3004=3004 0+3004=3004

Therefore the final answer is:

1=8,2=3004 1=8,2=3004

Answer

1=8,2=3004 1=8,2=3004

Exercise #9

−x−(−y) \frac{-x}{-(-y)}

Substitute the following into the equation above and calculate:

  1. y=−13,x=4 y=-\frac{1}{3},x=4

  2. y=+13,x=−4 y=+\frac{1}{3},x=-4

Video Solution

Step-by-Step Solution

Let's start with the first option.

Let's substitute the numbers in the given expression:

−4−(−(−13)= \frac{-4}{-(-(-\frac{1}{3})}=

Let's remember the rule:

−(−x)=+x -(-x)=+x

Therefore:

−4−(+13)= \frac{-4}{-(+\frac{1}{3})}=

Let's remember the rule:

−(+x)=−x -(+x)=-x

Now the exercise we got is:

−4−13= \frac{-4}{-\frac{1}{3}}=

Note that we are dividing between two negative numbers, so the result must be a positive number:

−−=+ \frac{-}{-}=+

413= \frac{4}{\frac{1}{3}}=

Let's convert the division to multiplication and remember to switch between the numerator and denominator of the simple fraction:

4×31=121=12 4\times\frac{3}{1}=\frac{12}{1}=12

Let's move on to solve the second option.

Let's substitute the numbers in the given expression:

−(−4)−(−(+13)= \frac{-(-4)}{-(-(+\frac{1}{3})}=

Let's remember the rules:

−(−x)=+x -(-x)=+x

−(+x)=−x -(+x)=-x

Now we get:

+4−(−13)=+4+13= \frac{+4}{-(-\frac{1}{3})}=\frac{+4}{+\frac{1}{3}}=

Note that we are dividing between two positive numbers, so the result must be a positive number:

++=+ \frac{+}{+}=+

Let's convert the division to multiplication and remember to switch between the numerator and denominator of the simple fraction:

4×31=121=12 4\times\frac{3}{1}=\frac{12}{1}=12

The final answer is:

1,2=+12 1,2=+12

Answer

1,2=+12 1,2=+12

Exercise #10

a⋅b+1= a\cdot b+1=

Replace and calculate if a=2,b=−2 a=2,b=-2

Video Solution

Step-by-Step Solution

Let's begin by inserting the given data into the formula:

2×(−2)+1= 2\times(-2)+1=

Remembering the rule:

(+x)×(−x)=−x (+x)\times(-x)=-x

Let's now solve the multiplication operation:

2×(−2)=−4 2\times(-2)=-4

In order to obtain the following expression:

−4+1= -4+1=

Therefore, the answer is:

−3 -3

Answer

−3 -3

Exercise #11

b⋅(a+4)= b\cdot(a+4)=

Replace and calculate if a=−6,b=−2 a=-6,b=-2

Video Solution

Step-by-Step Solution

Let's begin by inserting the known data into the formula:

−6×(−2+4)= -6\times(-2+4)=

First, let's solve the expression inside of the parentheses:

−2+4=2 -2+4=2

We should obtain the following expression:

−6×2= -6\times2=

Remembering the rule:

(−x)×(+x)=−x (-x)\times(+x)=-x

The answer should be:

−12 -12

Answer

−12 -12

Exercise #12

a⋅(a⋅b+3)= a\cdot(a\cdot b+3)=

Replace and calculate if a=−1,b=5 a=-1,b=5

Video Solution

Step-by-Step Solution

Let's begin by inserting the numbers into the formula:

−1×(−1×5+3)= -1\times(-1\times5+3)=

We must remember the following rule:

(−x)×(+x)=−x (-x)\times(+x)=-x

Let's now solve the expression inside of the parentheses:

(−1×5+3)= (-1\times5+3)=

−1×5=−5 -1\times5=-5

−5+3=−2 -5+3=-2

We should obtain the following expression:

−1×(−2)= -1\times(-2)=

Let's again remember the rule:

(−x)×(−x)=+x (-x)\times(-x)=+x

Therefore, the correct answer is:

2 2

Answer

2 2

Exercise #13

a+b⋅(a+1)= a+b\cdot(a+1)=

Replace and calculate if a=2,b=−3 a=2,b=-3

Video Solution

Step-by-Step Solution

Let's substitute the numbers into the formula:

2+(−3)×(2+1)= 2+(-3)\times(2+1)=

Let's remember the rule:

+(−x)=−x +(-x)=-x

Let's write the exercise in the appropriate form:

2−3×(2+1)= 2-3\times(2+1)=

Let's solve the expression in parentheses:

2+1=3 2+1=3

Now we get the exercise:

2−3×3= 2-3\times3=

Now let's solve the multiplication exercise:

3×3=9 3\times3=9

Now we get the exercise:

2−9= 2-9=

Therefore, the answer is:

−7 -7

Answer

−7 -7

Exercise #14

Look at the algebraic expression:

−x:yz -\frac{x:y}{z}

Substitute and calculate:

  1. x=y,z=−3 x=y,z=-3

  2. x=z,y=−4.4 x=z,y=-4.4

Video Solution

Step-by-Step Solution

Let's start with the first option.

Let's substitute the data into the expression:

−y:y−3= -\frac{y:y}{-3}=

Note that we are dividing between two negative numbers, therefore the result must be a positive number:

−−=+ \frac{-}{-}=+

+y:y3= +\frac{y:y}{3}=

Let's remember the rule that any number divided by itself equals 1, therefore:

yy=1 \frac{y}{y}=1

Now we have:

13 \frac{1}{3}

Let's continue with the second option.

Let's substitute the data into the expression:

−z:−4.4z= -\frac{z:-4.4}{z}=

Let's now reduce z z in both numerator and denominator of the fraction to get:

−(1:−4.4)= -(1:-4.4)=

Let's next write the exercise as a simple fraction:

−1−4.4= -\frac{1}{-4.4}=

Note that we are dividing between two negative numbers, therefore the result must be a positive number:

−−=+ \frac{-}{-}=+

Let's convert 4.4 into a simple fraction:

+1425= +\frac{1}{4\frac{2}{5}}=

Let's write the denominator fraction as a complex fraction:

+1425=1225= +\frac{1}{4\frac{2}{5}}=\frac{1}{\frac{22}{5}}=

Let's convert the fraction to a multiplication exercise remembering to switch between numerator and denominator:

1225=1×522=522 \frac{1}{\frac{22}{5}}=1\times\frac{5}{22}=\frac{5}{22}

Therefore the final answer is:

1=+13,2=+522 1=+\frac{1}{3},2=+\frac{5}{22}

Answer

1=+13,2=+522 1=+\frac{1}{3},2=+\frac{5}{22}

Exercise #15

Look at the following expression:

mn+3(−m) \frac{m}{n}+3(-m)


Substitute and calculate:

  1. m=3,n=−0.2 m=3,n=-0.2

  2. m=−4,n=−3 m=-4,n=-3

Video Solution

Step-by-Step Solution

Let's start with the first option.

Let's substitute the given data into the expression:

3−0.2+3(−3)= \frac{3}{-0.2}+3(-3)=

We'll next solve the exercise from left to right, first converting 0.2 into a simple fraction:

3−15+3(−3)= \frac{3}{-\frac{1}{5}}+3(-3)=

Now let's solve the multiplication problem, remembering that when we multiply a positive number by a negative number, the result must be negative:

3×(−3)=−9 3\times(-3)=-9

Now we have the exercise:

3−15+(−9)= \frac{3}{-\frac{1}{5}}+(-9)=

Let's convert the division problem to a multiplication problem, remembering to switch between the numerator and denominator of the fraction:

3×−51+(−9)= 3\times-\frac{5}{1}+(-9)=

Let's take -9 out of the parentheses and keep the appropriate sign:

3×(−5)1−9= \frac{3\times(-5)}{1}-9=

3×(−5)−9= 3\times(-5)-9=

−15−9=−24 -15-9=-24

Let's continue with the second option.

First we'll substitute the given data into the expression:

−4−3+3(−(−4))= \frac{-4}{-3}+3(-(-4))=

Let's next solve the exercise from left to right.

Note that we are dividing a negative number by a negative number, so the result must be positive:

43+3(−(−4))= \frac{4}{3}+3(-(-4))=

Let's open the parentheses and keep the appropriate sign:

43+3×(4)= \frac{4}{3}+3\times(4)=

Let's solve the multiplication problem:

43+12= \frac{4}{3}+12=

Let's break down the fraction into an addition problem:

3+13+12=33+13+12=1+13+12=1313 \frac{3+1}{3}+12=\frac{3}{3}+\frac{1}{3}+12=1+\frac{1}{3}+12=13\frac{1}{3}

Therefore, the final answer is:

1=−24,2=1313 1=-24,2=13\frac{1}{3}

Answer

1=−24,2=+1313 1=-24,2=+13\frac{1}{3}

Exercise #16

Look at the following algebraic expression:

m:−3m+4 m:-3m+4

Calculate when: m=2 m=2

Calculate when: m=−12 m=-\frac{1}{2}

Video Solution

Step-by-Step Solution

Let's start with the first option.

Let's write the division exercise in the expression as a simple fraction:

m−3m+4= \frac{m}{-3m}+4=

Note that we can reduce the m in both the numerator and denominator of the fraction to get:

1−3+4= \frac{1}{-3}+4=

Since we are dividing a negative number by a positive number, we will get a negative result:

−13+4=323 -\frac{1}{3}+4=3\frac{2}{3}

Let's continue with the second option.

Since in the previous exercise we saw that we can reduce the m in the numerator and denominator of the fraction, we'll do the same thing here and therefore reach the same result:

323 3\frac{2}{3}

Therefore, the final answer is that for any m the expression will equal -3 and two thirds.

Answer

For each m the value of the expression will be +323 +3\frac{2}{3} .