Question

FAN AND MEDAL. algebra review help ):
If you were to use the substitution method to solve the following system, choose the new equation after the expression equivalent to x from the first equation is substituted into the second equation.

-x + 5y = 1
2x + 4y = -4

2(-5y + 1) + 4y = -4

2x + 4(-5y + 1) = -4

2x + 4(5y - 1) = -4

2(5y - 1) + 4y = -4

Answer 1

1) -x + 5y = 1
2) 2x + 4y = -4

From 1):
-x = 1 - 5y
3) x = 5y - 1

From 2):
2x + 4y = -4
2(5y - 1) + 4y = -4
10 y - 2 + 4y = -4
14 y = -4 + 2
14 y = -2
y = -1/7

From 3):

x = 5y - 1
x = 5(-1/7) - 1
x = -5/7 - 1
x = -12/7

Answer 2

well you are making x the subject in the 1st equation

add x to both sides

5y = 1 + x

now subtract 1

x = 5y - 1

now substitute this into the 2nd equation.

Answer 3

I substitute it into y right?

Answer 4

You substitute the x = 5y - 1 into the x in 2x + 4y = -4, so that you get:
2(5y - 1) + 4y = -4

Answer 5

youre awesome. thank you (:

Answer 6

I'm more than happy to help! :)
@campbell_st did most of the explaining though

Answer 7

fanned both <3