You can put this solution on YOUR website!
Because of the x squared term, this is a quadratic equation. To solve a quadratic equation we want one side to be zero. Subtracing 4 from each side we get:
Now we factor (or use the Quadratic Formula). This factors easily as a difference of squares:
(4+x)(4-x) = 0
From the Zero Product Property we know that one of these factors must be zero. So:
4+x = 0 or 4-x = 0
Solving each of these we get:
x = -4 or x = 4
These are the solutions to your equation.