How do you solve the following system using substitution?: #y=x-5, y=2x#

1 Answer
Oct 24, 2015

Answer:

#x=-5#
#y=-10#

Explanation:

You simply have to substitute #x# or #y# from the first equation to #x# or #y# in the second equation.

So in the first equation, the value of #y# is #x-5#. You just have to substitute this value into #y# in the second equation.

#[1]color(white)(XX)y=2x#

#[2]color(white)(XX)x-5=2x#

#[3]color(white)(XX)-5=2x-x#

#[4]color(white)(XX)color(blue)(x=-5)#

Now that we have the value of #x#, we can plug it into either of the two equations to solve for #y#.

#[1]color(white)(XX)y=x-5#

#[2]color(white)(XX)y=(-5)-5#

#[3]color(white)(XX)color(red)(y=-10)#