Question

Solve this question using the substitution method.

1) Y=1-2x
-4x+3y=-17
what is x?
what is y?

2) x+3y=9
2x+3y=15


please provide the work.

Answer 1

Y=1-2x
-4x+3y=-17

Plug in y into -4x+3y=-17
-4x+3 (1-2x)=-17
-4x+3-6x=-17
-10x+3=-17
-3 both sides
-10x=-20
÷-10 both sides
x=2
plug in x to find y
y=1-2 (2)
y=1-4
y=-3

x+3y=9
2x+3y=15

make first equation into x= form
-3y both sides
x=-3y+9
2x+3y=15
plug in x into 2x+3y=15
2 (-3y+9)+3y=15
-6y+18+3y=15
-3y+18=15
-18 both sides
-3y=-3
÷-3 both sides
y=1
plug in y
x+3 (1)=9
x+3=9
-3 both sides
x=6