Suatu fungsi dirumuskan f(x) =ax +b. Jika f(2)=5 dan f(1)=2 ,maka tentukan: a. Nilai a dan b b. Bayangan dari -3

f(x) = ax + b
f(2) = 2a + b = 5
f(1) = a + b = 2
-------------------------(-)
a = 3
a + b = 2
3 + b = 2
b = 2 - 3 = - 1

f(x) = 3x - 1
f(-3) = 3(-3) - 1 = (-10)