Jika f(-2)=-11 dan f(4)=7, nilai a+b adalah…
(A) 3(B) -2(C) -5(D) -8
Diketahui fungsi f(x)=ax+b
Jawaban:
B (-2)
Penjelasan dengan langkah-langkah:
-11 = -2a + b ….(1)
7 = 4a + b …..(2)
eliminasi b (pers. 1 – 2)
-18 = -6a
a = -18 / -6
a = 3
-11 = -2(3) + b
-11 = -6 + b
b = -11 + 6
b = -5
a + b = 3 + (-5) = -2