How do you solve #2x + y = 1# and #4x + 2y = -2# using substitution?

1 Answer
May 19, 2017

Answer:

Solve the first equation for #y# and put it into the second equation.

Explanation:

We're going to have to plug one equation into the other if we want to solve for #x# and #y#. First, we'll take the first equation and subtract #2x# from each side so that the equation is written in terms of #y#:

#y=-2x+1#

Next, we substitute the #y# in the second equation with the first equation and solve for #x#:

#4x+2(2x+1)=-2#
#4x+4x+2=-2#
#8x+2=-2#
#8x=-4#
#x=-1/2#

To solve for #y#, let's take our first equation and plug in our answer for #x#:

#y=-2(-1/2)+1#
#y=1+1#
#y=2#