Diberikan fungsi f(x+3)=x2+2x Tentukan A. Bentuk fungsi f(x) B. Nilai dari f(-5)

f(x+3)= x^2 + 2x
= (x+3)^2 + 2(x+3)
= (x^2 + 6x + 9) + 2x + 6
f(x)= x^2 + 8x + 15

f(-5)= (-5)^2 + 8(-5) + 15
= 40 - 40
= 0

Kelas 8 Matematika
Bab Fungsi

a] f(x + 3) = x² + 2x
f(x - 3 + 3) = (x - 3)² + 2(x - 3)
f(x) = x² - 6x + 9 + 2x - 6
f(x) = x² - 4x + 3

b] f(-5) = (-5)² - 4 . (-5) + 3
f(-5) = 25 + 20 - 3
f(-5) = 42