Question

3x – 3y = -9 4x + 4y= 12 show me the steps for substitution?

Answer 1

Answer:

y=3 and x=0

Step-by-step explanation:

3x−3y=−9. i'm going to solve for x.

3x−3y+3y=−9+3y

3x=3y−9

3x/3=(3y-9)/3  to isolate x we have to divide everything by 3

x=y−3

so now that we have x we can substitute it in 4x+4y=12

4(y-3)+4y=12

4y-12+4y=12

8y-12=12

8y-12+12=12+12

8y=24

8y/8=24/8

y=3

we have y which equals 3, so now we can substitute it into any equation so solve for x again.

3x – 3y = -9

3x-3(3)=-9

3x-9=-9

3x-9+9=-9+9

3x=0

3x/3=0/3

x=0

so, final answers are y=3 and x=0

checking our work:

3(0)-3(3)=-9

0-9=-9

-9=-9 true

4(0)+4(3)=12

0+12=12

12=12 true