diketahui fungsi dengan f(x)=x2-2x-8

a. daerah hasi = {x | x € R}

b. nilai f(-3) = (-3)^2 - 2 (-3) - 8 = 9 + 6 - 8 = 7
nilai f(5) = (5)^2 - 2(5) - 8 = 25 - 10 - 8 = 7

c. x^2 - 2x - 8 = 27
x^2 - 2x - 8 - 27 = 0
x^2 - 2x - 35 = 0
(x - 7) (x + 5) =0
x - 7 = 0 ==> x = 7
atau x + 5 = 0 ==> x = -5
jadi x = 7 atau x = -5