How do you solve #y=x-4# and #y=2x# using substitution?
We know that
This must mean that
Now we know that
the value of
given equations are
Substitution means plugging one equation to another to solve for a variable, so:
By plugging it in, you get
Move variables to one side and constants in another
Since we found x, we can find y by plugging x back into either equations. Answer would be the same. To prove this, I'll plug x into both equations.