# Thread: Need help solving an equation.

1. ## Need help solving an equation.

I have no idea how to solve equations with modulus signs in. Do I take the modulus out and go through the equation with the four possibilities:

Positive sign, negative sign
Negative sign, negative sign
Positive sign, positive sign
Negative sign, positive sign?

Help would be greatly appreciated!

2. Originally Posted by bluebiro
I have no idea how to solve equations with modulus signs in. Do I take the modulus out and go through the equation with the four possibilities:

Positive sign, negative sign
Negative sign, negative sign
Positive sign, positive sign
Negative sign, positive sign?

Help would be greatly appreciated!
Let $y=|x-3|$ then $y^2 - 4y = 12 \implies y^2 - 4y - 12 = 0$

Now solve for $y$.
And then you can solve for $x$.