Solving systems of equations by substitution?

Question

{3x-2y=5, x+2y=15}

Answer 1

Substitution method :

3x - 2y = 5

Add 2y to each side

3x = 5 + 2y

2y = 3x - 5

x + 2y = 15

Substitute 2y = 3x - 5 in the equation x + 2y = 15

x + (3x - 5) = 15

4x - 5 = 15

4x = 20

x = 5

Substitute x = 5 in the equation x + 2y = 15

5 + 2y = 15

2y = 10

y = 5

The solutions of equations : x = 5 and y = 5.

Answer 2

Substitution method

The equations are 3x - 2y = 5 and x + 2y = 15

Solve the second equation for x  since the coefficient of x  is 1.

Second equation : x + 2y = 15

x = - 2y + 15

Find the value of y  by substituting - 2y + 15  for x  in the First equation.

First equation : 3x -2y = 5

3(-2y + 15) - 2y = 5

-6y + 45 - 2y = 5

- 8y  = - 45 + 5

y = -40/-8

y = 5

Substitute 5 for y in either equation to find the value of x.

Second equation x + 2y = 15

x + 2(5) = 15

x + 10 = 15

x = 15 -10

x = 5

Solution x = 5 and y = 5.