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

1 Answer
Oct 24, 2015

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)