Question

Complete the square to determine the minimum or maximum value of the function defined by the expression. x2 − 12x − 2

Answer 1

The minimum value = -38

Explanation:

∵ f(x) = x² - 12x - 2

∵ -12x ÷ 2 = -6x ⇒ -6 × x

∴ (x - 6)² = x² - 12x + 36

∴ Add and subtract 36 in f(x)

∴ f(x) = (x² - 12x + 36) - 36 - 2

∴ f(x) = (x - 6)² - 38 ⇒ completing square

∴ The vertex of the parabola is (6 , -38)

∵ Its minimum point because the coefficient of x² is positive

∴ The minimum value = -38