Question

When using the substitution method, what expression for x in the first equation would be substituted in the second equation?

x + 3y = –7
2x + 4y = –4
Choices:

A.3y – 7
B.3y + 7
C.–3y – 7
D.–3y + 7

Answer 1

2x+6y =-14, x= -7-6y =c

Answer 2

x + 3y = –7
x = -3y-7

is C

Answer 3

x + 3y = –7
2x + 4y = –4


x=-7-3y
2(-7-3y)+4y=-4
-14-6y+4y=-4
-2y=10
y=-5

x=-7-3(-5)=-7+15=8