diketahui f(x) = 8-2x jika f(a) = -2 dan f(3)= b maka nilai a-b adalah

f(a) =8-2a
-2 = 8-2a
a = 10/2 = 5

f(3) = 8-2(3)
b = 8-6 = 2

maka
a-b = 5-2 =3

Bab Fungsi
Matematika SMP Kelas VIII

f(x) = 8 - 2x
f(a) = 8 - 2a = -2
-2a = -2 -8
a = -10 : -2
a = 5

f(3) = 8 - 2 . 3 = b
b = 8 - 6
b = 2

a - b = 5 - 2 = 3