Question

Solve the system of linear equations by substitution. x=2y+7 3x−2y=3

Answer 1

The system of equation
First equation
x = 2y + 7
Second equation
3x - 2y = 3

Substitute x with (2y + 7) in the second equation
3x - 2y = 3
3(2y + 7) - 2y = 3

use distributive property
3(2y) + 3(7) - 2y = 3
6y + 21 - 2y = 3

add like terms
6y - 2y + 21 = 3
4y = 3 - 21
4y = -18
  y = -18/4
  y = -4.5

Substitute y with its value, which is -4.5, in the first equation
x = 2y + 7
x = 2(-4.5) + 7
x = -9 + 7
x = -2

The solution is
(x,y) = (-2, -4.5)