How do you solve x=-2yx=2y and x=2-4yx=24y using the substitution method?

1 Answer
Mar 30, 2018

(x,y)to(-2,1)(x,y)(2,1)

Explanation:

x=-2yto(1)x=2y(1)

x=2-4yto(2)x=24y(2)

"since both equations express x in terms of y we can"since both equations express x in terms of y we can
"equate the right sides"equate the right sides

rArr-2y=2-4y2y=24y

"add 4y to both sides"add 4y to both sides

-2y+4y=2cancel(-4y)cancel(+4y)

rArr2y=2

"divide both sides by 2"

rArry=1

"substituting "y=1" into equation "(1)" gives x"

rArrx=-2xx1=-2

"the solution is "(x,y)to(-2,1)