How do you solve the following system?: 7y=4- 2x , 2x – y = -4

1 Answer
Jan 2, 2016

To solve, rearrange one equation so that one variable is the subject, then substitute that equation into the other equation, and solve from there.

Explanation:

Example method for this question would be:
(1) 7y=4-2x
(2) 2x-y=-4
rearrange (2) to give:
(3) 2x=y-4
substitute (3) into (1):
7y=4-(y-4)
8y=8
y=1
Then substitute y=1 into (2)
2x-1=-4
2x=-3
x=-3/2

Check by substituting both into (1).
7=4+3