40%= 0.40 if you think of the decimal being at the end of the number (40.%) than just move the decimal twice makes it 0.40
I will get you started.
x^2+4x-4 = 8
x^2 + 4x - 4 - 8 = 0
x^2 + 4x - 12 = 0
You must now use the quadratic formula.
In the formula, a = 1, b = 4, and c = -12.
Take it from here.
