Question

Solve using substitution.

2x-3y
x+y=9

just so you know, I know the answer its (3,6). I just need the explanation on how to get that answer using substitution.

Answer 1

(3,6)

Explanation:

2x-3y = -12

x+y=9. Solve for either y or x

-x. -x

y = -x + 9. Substitute this for the y

2x-3(-x+9)= -12

2x +3x-27 = -12. Add like terms

5x -27 = -12

+27. +27. Inverse operations

5x = 15

÷5. ÷5

x = 3

x + y = 9

3 + y = 9. Substitute 3 for x

-3. -3. Inverse operations

y = 6