Explanation:
Simplifying
4x2 + -20 = 556
Reorder the terms:
-20 + 4x2 = 556
Solving
-20 + 4x2 = 556
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '20' to each side of the equation.
-20 + 20 + 4x2 = 556 + 20
Combine like terms: -20 + 20 = 0
0 + 4x2 = 556 + 20
4x2 = 556 + 20
Combine like terms: 556 + 20 = 576
4x2 = 576
Divide each side by '4'.
x2 = 144
Simplifying
x2 = 144
Take the square root of each side:
x = {-12, 12}