Simplifying X2 + -4 = 0 Reorder the terms: -4 + X2 = 0 Solving -4 + X2 = 0 Solving for variable 'X'. Move all terms containing X to the left, all other terms to the right. Add '4' to each side of the equation. -4 + 4 + X2 = 0 + 4 Combine like terms: -4 + 4 = 0 0 + X2 = 0 + 4 X2 = 0 + 4 Combine like terms: 0 + 4 = 4 X2 = 4 Simplifying X2 = 4 Take the square root of each side: X = {-2, 2}