Question

If f(x) = 4 – x2 and g(x) = 6x, which expression is equivalent to (g – f)(3)?

Answer 1

f(x) = 4 - x²    g(x) = 6x

(g - f)(x) = g(x) - f(x)

(g - f)(3) = g(3) - f(3)

g(x) = 6x

g(3) = 6*3 = 18

f(x) = 4 - x²

f(3) = 4 - 3² = 4 - 9 = -5

(g - f)(3) = g(3) - f(3) = 18 - (-5) = 18 + 5 = 23

 (g - f)(3) = 23