How do you solve #x = -5 + 2y# and #2x + 3y = 4# using substitution?

1 Answer
Aug 5, 2016

Answer:

To solve, substitute the #x# in the second equation for the #x# in the first equation.

Explanation:

The first equation is already solved for #x#, so let's put that equation into the second equation. It'll look like this:

#2(-5+2y)+3y=4#

Next, use the distributive property to simplify our equation:

#-10+4y+3y=4#

Now, let's combine #3y# and #4y# to make #7y#:

#-10+7y=4#

Next, add #10# to each side:

#7y=14#

The final step in solving for y is to divide each side by #7#:

#y=2#

We've now solved for y. Now, we have to solve for x. The easiest way to do this is to substitute our y-value into the first equation, since it's already solved for x:

#x=-5+2(2)#

#x=-5+4#

#x=-1#

Using our x and y value and combining them to get an ordered pair, we now have our answer: #(-1,2)#