Question

Jika f(x) = x pangkat 2 + 3x + m dan f(-2) = 18 . Nilai dari f(-1) adalah...?

Answer 1

F(x) = x^2 + 3x + m

f(-2) = (-2)^2 + 3(-2) + m
18 = 4 + (-6) + m
18 = 4 - 6 + m
18 = -2 + m
18+2 = m
20 = m

f(-1) = (-1)^2 + 3(-1) + 20
= 1 + (-3) + 20
= 1 - 3 + 20
f(-1) = 18

catatan : "^" adalah pangkat