Jika f(x+5)=x²+2x+1 maka f(3) cara panjang buat guru

Bab Fungsi
Matematika SMP Kelas VIII

x + 5 = 3
x = 3 - 5
x = -2

x² + 2x + 1
= (-2)² + 2 . (-2) + 1
= 4 - 4 + 1
= 1

atau

f(x + 5) = x² + 2x + 1
f(x - 5 + 5) = (x - 5)² + 2 . (x - 5) + 1
f(x) = x² - 10x + 25 + 2x - 10 + 1
f(x) = x² - 8x + 16

f(3) = 3² - 8 . 3 + 16
f(3) = 9 - 24 + 16
f(3) = 1