Question

Pada fungsi f(x) = x^{2} + x + 3.Jika f(a) = 9, maka nilai a adalah....

Answer 1

F(a)=a^2+a+3=9
a^3+a-6=0
(a+3)(a-2)=0
a=-3 a=2

Answer 2

F (x) = x² + x + 3
f (a) = 9
apabila a = 1
f (1) = 1² + 1 + 3 = 9
= 5 = 9 (tidak memenuhi)
apabila a = 2
f (2) = 2² + 2 + 3 = 9
= 9 (memenuhi)

jawaban = nilai a = 2