SAT Prep

Answer: E - The square of the solution of the equation is − 9. The arithmetic root must be greater or equal to zero.
− 5 − x≥0
5 + x≤0
x≤ − 5
Solve equation for x.
√(7 − x) = − 5 − x
(√(7 − x))² = ( − 5 − x)²
7 − x = 25 + 10x + x²
x² + 10x + x + 25 − 7 = 0
x² + 11x + 18 = 0
x² + 11x + 18 = x² + 9x + 2x + 18 = x(x + 9) + 2(x + 9) = (x + 9)(x + 2)
(x + 9)(x + 2) = 0
x = − 9 T
x = − 2 ⊥
x² = ( − 9)² = 81