Linear Equations with Two Variables: Using fractions

Examples with solutions for Linear Equations with Two Variables: Using fractions

Exercise #1

x2+y=3 \frac{x}{2}+y=3

x+2y=6 x+2y=6

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Solve the first equation for x x .
  • Step 2: Substitute this expression for x x into the second equation.
  • Step 3: Analyze the resulting equation for y y .
  • Step 4: Determine the relationship between the two equations.

Now, let's work through each step:
Step 1: Starting with the first equation x2+y=3 \frac{x}{2} + y = 3 , we solve for x x by isolating it:
Subtract y y from both sides:
x2=3y \frac{x}{2} = 3 - y
Multiply both sides by 2 to solve for x x :
x=2(3y)=62y x = 2(3 - y) = 6 - 2y

Step 2: Substitute x=62y x = 6 - 2y into the second equation x+2y=6 x + 2y = 6 :
(62y)+2y=6 (6 - 2y) + 2y = 6
Simplify:
6=6 6 = 6

Step 3: The equation 6=6 6 = 6 is always true, indicating there is no contradiction and hence infinitely many solutions when both conditions arise from manipulating consistent equations.

Step 4: Since manipulating these equations leads us to an identity, they are dependent; both equations are forms of the same linear equation x2+y=3 \frac{x}{2} + y = 3 . Each point on this line satisfies both equations, confirming infinite solutions.

Therefore, the solution to the system of equations is infinite solutions.

Answer

Infinite solutions

Exercise #2

x+3y2=0 \frac{x+3y}{2}=0

x+y=4 x+y=4

Video Solution

Step-by-Step Solution

To solve this system of linear equations, we'll employ the substitution method. The equations given are:

x+3y2=0 \frac{x+3y}{2} = 0

x+y=4 x + y = 4

Step 1: Solve the first equation for x x .

The equation x+3y2=0 \frac{x+3y}{2} = 0 can be simplified:

Multiply both sides by 2 to eliminate the fraction:

x+3y=0 x + 3y = 0

Solving for x x , we get:

x=3y x = -3y

Step 2: Substitute this expression for x x into the second equation.

Substitute x=3y x = -3y into x+y=4 x + y = 4 :

3y+y=4 -3y + y = 4

This simplifies to:

2y=4 -2y = 4

Step 3: Solve for y y .

Divide both sides by -2 to find y y :

y=2 y = -2

Step 4: Substitute y=2 y = -2 back into the expression for x x .

Using x=3y x = -3y :

x=3(2)=6 x = -3(-2) = 6

Thus, the solution to the system of equations is x=6 x = 6 and y=2 y = -2 .

Therefore, the solution to the problem is x=6,y=2 x = 6, y = -2 .

Answer

x=6,y=2 x=6,y=-2

Exercise #3

4x7y=3 4x-\frac{7}{y}=-3

5x+2y=7 5x+\frac{2}{y}=7

Video Solution

Step-by-Step Solution

To solve the system of equations, we will apply the substitution method:

We start with the given equations:

4x7y=3 4x - \frac{7}{y} = -3 (Equation 1)

5x+2y=7 5x + \frac{2}{y} = 7 (Equation 2)

Let's start by solving Equation 1 for 1y \frac{1}{y} :

4x7y=3 4x - \frac{7}{y} = -3

Rearrange to isolate 1y \frac{1}{y} :

7y=34x -\frac{7}{y} = -3 - 4x

Multiply through by -1 to simplify:

7y=4x+3 \frac{7}{y} = 4x + 3

1y=4x+37 \frac{1}{y} = \frac{4x + 3}{7} (Equation 3)

Now, substitute Equation 3 into Equation 2:

5x+2y=7 5x + \frac{2}{y} = 7

Replace 1y \frac{1}{y} from Equation 3:

5x+2(4x+37)=7 5x + 2 \left(\frac{4x + 3}{7}\right) = 7

Multiply both sides of the equation by 7 to eliminate the fraction:

35x+2(4x+3)=49 35x + 2(4x + 3) = 49

Expand and simplify:

35x+8x+6=49 35x + 8x + 6 = 49

43x+6=49 43x + 6 = 49

Subtract 6 from both sides:

43x=43 43x = 43

Divide by 43:

x=1 x = 1

Substitute x=1 x = 1 back into Equation 3 to solve for y y :

1y=4(1)+37 \frac{1}{y} = \frac{4(1) + 3}{7}

1y=4+37 \frac{1}{y} = \frac{4 + 3}{7}

1y=77 \frac{1}{y} = \frac{7}{7}

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

Therefore, y=1 y = 1

The solution to the system of equations is x=1,y=1 x = 1, y = 1 .

Answer

x=1,y=1 x=1,y=1

Exercise #4

2x3y=3 \frac{2x}{3}-y=3

x+3y=6 x+3y=6

Video Solution

Step-by-Step Solution

To solve this system of equations, we'll use the substitution method.

Here are the steps we will take:

  • Step 1: Solve the second equation x+3y=6x + 3y = 6 for xx.
  • Step 2: Substitute the expression for xx in the first equation 2x3y=3\frac{2x}{3} - y = 3.
  • Step 3: Solve the resulting equation for yy.
  • Step 4: Substitute back to find xx.

Let's begin:

Step 1: Solve x+3y=6x + 3y = 6 for xx:
x=63y x = 6 - 3y

Step 2: Substitute x=63yx = 6 - 3y into the first equation 2x3y=3\frac{2x}{3} - y = 3:
2(63y)3y=3 \frac{2(6 - 3y)}{3} - y = 3

Simplify the expression:
126y3y=3 \frac{12 - 6y}{3} - y = 3

This simplifies to:
42yy=3 4 - 2y - y = 3

Combine like terms:
43y=3 4 - 3y = 3

Isolate yy:
3y=34 -3y = 3 - 4
3y=1 -3y = -1
y=13 y = \frac{-1}{-3}
y=13 y = \frac{1}{3}

Step 3: With y=13y = \frac{1}{3}, substitute back into x=63yx = 6 - 3y:
x=63(13) x = 6 - 3\left(\frac{1}{3}\right)
x=61 x = 6 - 1
x=5 x = 5

Therefore, the solution to this system of equations is x=5,y=13\mathbf{x = 5, y = \frac{1}{3}}.

Referring to the choice list, the correct choice is Choice 3: x=5,y=13 x = 5, y = \frac{1}{3} .

Answer

x=5,y=13 x=5,y=\frac{1}{3}

Exercise #5

3x+3y=2 \frac{3}{x}+\frac{3}{y}=2

9x4y=7 \frac{9}{x}-\frac{4}{y}=-7

Video Solution

Step-by-Step Solution

To solve this system of linear equations, follow these steps:

  • Step 1: Examine and rearrange the first equation 3x+3y=2 \frac{3}{x} + \frac{3}{y} = 2 .
  • Step 2: Express one variable in terms of the other. We can isolate 3x\frac{3}{x} to get 3x=23y\frac{3}{x} = 2 - \frac{3}{y}.
  • Step 3: Substitute 3x=23y\frac{3}{x} = 2 - \frac{3}{y} into the second equation 9x4y=7\frac{9}{x} - \frac{4}{y} = -7.
  • Step 4: Replace 9x\frac{9}{x} with 3(23y)3\left(2 - \frac{3}{y}\right) leading to 3(23y)4y=73\left(2 - \frac{3}{y}\right) - \frac{4}{y} = -7.
  • Step 5: Simplify the equation: Distribute 33 into 23y2 - \frac{3}{y} to obtain (69y)4y=7(6 - \frac{9}{y}) - \frac{4}{y} = -7.
  • Step 6: Combine the terms to get 613y=76 - \frac{13}{y} = -7.
  • Step 7: Isolate 13y\frac{13}{y}: 13y=13\frac{13}{y} = 13.
  • Step 8: Solve for yy: Multiply both sides by yy, leading to 13=13y13 = 13y, hence y=1y = 1.
  • Step 9: Substitute y=1y = 1 back into 3x=23y\frac{3}{x} = 2 - \frac{3}{y}, resulting in 3x=23\frac{3}{x} = 2 - 3, or 3x=1\frac{3}{x} = -1.
  • Step 10: Solve for xx: Multiply both sides by xx, leading to 3=x3 = -x, thus x=3x = -3.

Therefore, the solution to the system of equations is x=3\boldsymbol{x = -3} and y=1\boldsymbol{y = 1}.

The correct choice among the given answer choices is the third option: x=3,y=1\boldsymbol{x = -3, y = 1}.

Answer

x=3,y=1 x=-3,y=1

Exercise #6

3x+1y=4 \frac{3}{x}+\frac{1}{y}=4

5x1y=4 \frac{5}{x}-\frac{1}{y}=4

Video Solution

Step-by-Step Solution

We begin by examining the given system of equations:

3x+1y=4 \frac{3}{x} + \frac{1}{y} = 4 --- (1)

5x1y=4 \frac{5}{x} - \frac{1}{y} = 4 --- (2)

Let's eliminate 1y \frac{1}{y} by adding equations (1) and (2):

(3x+1y)+(5x1y)=4+4 \left(\frac{3}{x} + \frac{1}{y}\right) + \left(\frac{5}{x} - \frac{1}{y}\right) = 4 + 4

3x+5x=8 \frac{3}{x} + \frac{5}{x} = 8

8x=8 \frac{8}{x} = 8

Solving for x x , we have:

x=1 x = 1

Now, substitute x=1 x = 1 back into equation (1):

31+1y=4 \frac{3}{1} + \frac{1}{y} = 4

3+1y=4 3 + \frac{1}{y} = 4

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

Solving for y y , we obtain:

y=1 y = 1

Thus, the solution to the system of equations is x=1 x = 1 and y=1 y = 1 .

The correct answer choice is: x=1,y=1 x=1,y=1 .

Answer

x=1,y=1 x=1,y=1