# Thread: Solving simultaneous equations using substitution method.

1. ## Solving simultaneous equations using substitution method.

I need help with the following problem. I forgot how to do these and this assignment is due tomorrow. Any help would be greatly appreciated!

Solve by substitution method:

x + y = 2
y = x^2 - 4

2. Substitute the second one into the first one. Thus, you get :

$x + (x^2 - 4) = 2$

$x + x^2 = 6$

$x^2 + x - 6 = 0$

Now solve for $x$ using the factorization method or the quadratic formula, then substitute back the $x$'s into the first equation to find the $y$'s

3. Thanks alot. Got it now. =]