Inequalities: Applying the formula

Examples with solutions for Inequalities: Applying the formula

Exercise #1

Solve the inequality:


7+2x<15 7 + 2x < 15

Step-by-Step Solution

To solve the inequality 7+2x<15 7 + 2x < 15 , we start by isolating the variable x x .

First, subtract 7 from both sides of the inequality:

7+2x7<157 7 + 2x - 7 < 15 - 7

Simplifying this, we get:

2x<8 2x < 8

Next, divide both sides by 2 to solve for x x :

2x2<82 \frac{2x}{2} < \frac{8}{2}

Thus, the solution is:

x<4 x < 4

Answer

x < 4

Exercise #2

Solve the following inequality:

5x+8<9

Video Solution

Step-by-Step Solution

This is an inequality problem. The inequality is actually an exercise we solve in a completely normal way, except in the case that we multiply or divide by negative.

Let's start by moving the sections:

5X+8<9

5X<9-8

5X<1

We divide by 5:

X<1/5

And this is the solution!

 

Answer

x<\frac{1}{5}

Exercise #3

Solve the inequality:


5-3x>-10

Video Solution

Step-by-Step Solution

Inequality equations will be solved like a regular equation, except for one rule:

If we multiply the entire equation by a negative, we will reverse the inequality sign.

 

We start by moving the sections, so that one side has the variables and the other does not:

-3x>-10-5

-3x>-15

Divide by 3

-x>-5

Divide by negative 1 (to get rid of the negative) and remember to reverse the sign of the equation.

x<5

Answer

5 > x

Exercise #4

Solve the following inequality:

3x+410 3x+4 \leq 10

Step-by-Step Solution

To solve the inequality 3x+410 3x+4 \leq 10 , follow these steps:

1. Subtract 4 from both sides: 3x6 3x \leq 6 .

2. Divide both sides by 3: x2 x \leq 2 .

Answer

x2 x \leq 2

Exercise #5

Solve the following inequality:

2x5>3 2x-5 > 3

Step-by-Step Solution

To solve the inequality 2x5>3 2x-5 > 3 , follow these steps:

1. Add 5 to both sides: 2x>8 2x > 8 .

2. Divide both sides by 2: x>4 x > 4 .

Answer

x>4 x > 4

Exercise #6

Solve the following inequality:

4x+311 4x+3 \geq 11

Step-by-Step Solution

To solve the inequality 4x+311 4x+3 \geq 11 , follow these steps:

1. Subtract 3 from both sides: 4x8 4x \geq 8 .

2. Divide both sides by 4: x2 x \geq 2 .

Answer

x2 x \geq 2

Exercise #7

Solve the following inequality:

6x2<4 6x - 2 < 4

Step-by-Step Solution

To solve the inequality 6x2<4 6x - 2 < 4 , follow these steps:

1. Add 2 to both sides: 6x<6 6x < 6 .

2. Divide both sides by 6: x<1 x < 1 .

Answer

x<1 x < 1

Exercise #8

Solve the inequality:

4x + 7 > 19

Step-by-Step Solution

To solve the inequality 4x+7>19 4x + 7 > 19 , follow these steps:

1. Subtract 7 from both sides to isolate the term with x x on one side.

4x+77>197 4x + 7 - 7 > 19 - 7

2. This simplifies to:

4x>12 4x > 12

3. Next, divide each side by 4 to solve for x x .

x>124 x > \frac{12}{4}

4. This simplifies further:

x>3 x > 3

Therefore, the solution is x>3 x > 3 .

Answer

x>3 x > 3

Exercise #9

Solve the inequality:


2x+93 -2x + 9 \leq 3

Step-by-Step Solution

To solve the inequality 2x+93 -2x + 9 \leq 3 , follow these steps:

1. Subtract 9 from both sides:

2x+9939 -2x + 9 - 9 \leq 3 - 9

2. This simplifies to:

2x6 -2x \leq -6

3. Divide each side by -2, remembering to reverse the inequality sign since dividing by a negative number:

x62 x \geq \frac{-6}{-2}

4. Simplifying gives:

x3 x \geq 3

Thus, the solution is x3 x \leq 3 .

Answer

x3 x \geq 3

Exercise #10

Solve the inequality:

6x - 4 < 14

Step-by-Step Solution

To solve the inequality 6x4<14 6x - 4 < 14 , follow these steps:

1. Add 4 to both sides:

6x4+4<14+4 6x - 4 + 4 < 14 + 4

2. Simplify:

6x<18 6x < 18

3. Divide both sides by 6 to solve for x x :

x<186 x < \frac{18}{6}

4. This simplifies to:

x<3 x < 3

Thus, the solution is x<3 x < 3 .

Answer

x < \frac{9}{3}

Exercise #11

Solve the inequality:

5x+b > 2x+3

Step-by-Step Solution

To solve the inequality 5x+b > 2x+3 , we will follow these steps:

  • Subtract 2x 2x from both sides: 3x + b > 3

  • Subtract b b from both sides: 3x > 3 - b

  • Divide both sides by 3 3 : x > -\frac{1}{3}b + 1

Answer

x > -\frac{1}{3}b+1

Exercise #12

Solve the inequality:

6x+d < 3x+1

Step-by-Step Solution

To solve the inequality 6x+d < 3x+1 , we follow these steps:

  • Subtract 3x 3x from both sides: 3x + d < 1

  • Subtract d d from both sides: 3x < 1 - d

  • Divide both sides by 3 3 : x < -\frac{1}{3}d+\frac{1}{3}

Answer

x < -\frac{1}{3}d+\frac{1}{3}

Exercise #13

Solve the inequality:

7x+c4x2 7x+c \leq 4x-2

Step-by-Step Solution

To solve the inequality7x+c4x2 7x+c \leq 4x-2 , we follow these steps:

  • Subtract 4x 4x from both sides: 3x+c2 3x + c \leq -2

  • Subtract c c from both sides: 3x2c 3x \leq -2 - c

  • Divide both sides by 3 3 : xc+23 x \leq -\frac{c+2}{3}

Answer

xc+23 x \leq -\frac{c+2}{3}

Exercise #14

When are the following inequalities satisfied?

3x+4<9

3 < x+5

Video Solution

Step-by-Step Solution

To solve the given inequalities, we will handle each one individually and then find the valid range of x x where both are satisfied:

  • First Inequality: 3x+4<9 3x + 4 < 9
    Solve for x x by first subtracting 4 from both sides:
    3x+44<943x<5 3x + 4 - 4 < 9 - 4 \Rightarrow 3x < 5 .
    Next, divide both sides by 3 to solve for x x :
    x<53 x < \frac{5}{3} .
  • Second Inequality: 3<x+5 3 < x + 5
    Solve for x x by subtracting 5 from both sides:
    35<x+552<x 3 - 5 < x + 5 - 5 \Rightarrow -2 < x .

Now we combine the solutions from both inequalities:

  • From the first inequality, we have: x<53 x < \frac{5}{3} .
  • From the second inequality, we have: x>2 x > -2 .

Therefore, combining these results, the solution is the intersection of the two ranges:

2<x<53-2 < x < \frac{5}{3}, which can be expressed as 2<x<123 -2 < x < 1\frac{2}{3} .

The final solution is 2<x<123 -2 < x < 1\frac{2}{3} .

Answer

-2 < x < 1\frac{2}{3}

Exercise #15

Find when the inequality is satisfied:

-3x+15<3x<4x+8

Video Solution

Step-by-Step Solution

To solve this problem effectively, we will proceed by solving each inequality separately:

  • Step 1: Solve the inequality 3x+15<3x-3x + 15 < 3x.
    • Add 3x3x to both sides to get: 15<6x15 < 6x.
    • Divide both sides by 66 to solve for xx: x>156x > \frac{15}{6}, simplifying to x>2.5x > 2.5.
  • Step 2: Solve the second inequality 3x<4x+83x < 4x + 8.
    • Subtract 3x3x from both sides to isolate xx: 0<x+80 < x + 8.
    • Subtract 88 from both sides to find: 8<x-8 < x.
  • Step 3: Find the overlap of the solutions.
    • The solution to the inequalities 8<x-8 < x and x>2.5x > 2.5 is simply x>2.5x > 2.5 since x>2.5x > 2.5 is more restrictive.

Thus, the values of x x that satisfy the original compound inequality are those for which x>2.5x > 2.5.

Therefore, the solution to the problem is 2.5<x 2.5 < x .

Answer

2.5 < x

Exercise #16

Solve the inequality:

8x+a < 3x-4

Video Solution

Step-by-Step Solution

Solving an inequality equation is just like a normal equation. We start by trying to isolate the variable (X).

It is important to note that in this equation there are two variables (X and a), so we may not reach a final result.

 8x+a<3x-4

We move the sections

8x-3x<-4-a

We reduce the terms

5x<-4-a

We divide by 5

x< -a/5 -4/5

And this is the solution!

 

Answer

x < -\frac{1}{5}a-\frac{4}{5}

Exercise #17

Find a a a so that:

0 < 8a+4 ≤ -a+9

Video Solution

Step-by-Step Solution

To solve this problem, we'll break it down into manageable steps:

The problem asks us to find a a satisfying two conditions simultaneously: 0<8a+4 0 < 8a + 4 and 8a+4a+9 8a + 4 \leq -a + 9 .

  • Step 1: Solve the first inequality.
  • The inequality 0<8a+4 0 < 8a + 4 can be simplified by subtracting 4 from both sides:

    4<8a -4 < 8a

    Next, divide each side by 8 to isolate a a :

    12<a -\frac{1}{2} < a
  • Step 2: Solve the second inequality.
  • The inequality 8a+4a+9 8a + 4 \leq -a + 9 can be simplified. Begin by adding a a to both sides to gather all a a -terms on one side:

    9a+49 9a + 4 \leq 9

    Subtract 4 from both sides:

    9a5 9a \leq 5

    Finally, divide each side by 9 to solve for a a :

    a59 a \leq \frac{5}{9}
  • Step 3: Combine the results of these inequalities.
  • We now combine the results from step 1 and step 2:

    The condition from step 1 is 12<a -\frac{1}{2} < a .

    The condition from step 2 is a59 a \leq \frac{5}{9} .

    Together, these conditions provide the range:

    12<a59 -\frac{1}{2} < a \leq \frac{5}{9}

The solution set is 12<a59 -\frac{1}{2} < a \leq \frac{5}{9} .

Therefore, the correct answer choice is: 12<a59 -\frac{1}{2} < a \leq \frac{5}{9} .

Answer

-\frac{1}{2} < a ≤ \frac{5}{9}

Exercise #18

which value of X satisfies:

8x< 3x+9

but does not exist in:

5x+4<0

Video Solution

Step-by-Step Solution

To solve this problem, we will address each inequality separately and examine the conditions:

Step 1: Solving the First Inequality

The first inequality is 8x<3x+9 8x < 3x + 9 .

  • Subtract 3x 3x from both sides to isolate terms with x x :

8x3x<9 8x - 3x < 9

5x<9 5x < 9

  • Divide both sides by 5 to solve for x x :

x<95 x < \frac{9}{5}

Thus, the solution to the first inequality is x<1.8 x < 1.8 .

Step 2: Solving the Second Inequality

The second inequality is 5x+4<0 5x + 4 < 0 .

  • Subtract 4 from both sides:

5x<4 5x < -4

  • Divide both sides by 5:

x<45 x < -\frac{4}{5}

Thus, x<0.8 x < -0.8 .

Step 3: Analyzing the Combined Conditions

  • We need to find the values of x x that satisfy x<1.8 x < 1.8 (from Step 1) but do not satisfy x<0.8 x < -0.8 (from Step 2).
  • This indicates x x should be greater than or equal to 0.8-0.8 and still less than 1.8 1.8 .

Therefore, the solution is 0.8x<1.8 -0.8 \leq x < 1.8 .

Thus, the value of x x satisfies the desired condition, which corresponds to choice 3 in the options provided.

Therefore, the solution to the problem is 0.8x<1.8 -0.8 \leq x < 1.8 .

Answer

-0.8 ≤ x < 1.8

Exercise #19

5a+14 < -2x < 3a+8 Calculate X in terms of a a

given that 0 < a .

Video Solution

Answer

No solution