Question

Solve the following system using the substitution method:
3x + y = -3
y = 2x + 7

Answer 1

we see that y = -3x-3
substitute that into the other euation to get

-3x-3 = 2x+7
-5x = 10
x = -2
so, y = -3(-2)-3 = 3

check to make sure (-2,3) solves both equations.

Answer 2

3x + y = -3
y = 2x + 7

3x + 2x + 7 = -3

5x = -10

x = -2

y - (2 * -2) + 7

y = 7 - 4

y = 3

Answer 3

3x+y=3
Y=2x-7