Let f(x) = x2 − 81. Find f−1(x).
f(x) = x² - 81Finding f⁻¹(x) the inverse functionLet y = f(x) and solve for x.y = x² - 81y + 81 = x² x² = y + 81x = √(y + 81)Recall f(x) = y, that means x = f⁻¹(y)x = √(y + 81)f⁻¹(y) = √(y + 81)Therefore f⁻¹(x) = √(x + 81)
