tolong donggg, butuh banget bantuannyaaa, sekalian caranya yahhh :)) tengkyuu

f(x) = ax + b, f(x-1) = a(x-1)+ b
f(x) - f(x-1) = 5
(ax + b) - { a(x-1) + b } = 5
ax + b - { ax -a +b } = 5
ax + b -ax + a - b = 5
a = 5
f (x) = 5x + b.
f (1) = 2
5.1 + b = 2
5 + b = 2
b = 2 -5
b = -3
Jadi f(x) = 5x - 3.