Question

Diketahui rumus fungsi f(x) = ax+b. jika f(3)=15 dan f(-2) =10 tentukanlah..

a) nilai a dan b
b) rumua fungsi f (x)
c) nilai f(7)

Answer 1

F(3) = 3a+b   ⇒ 15 =3a + b
f(-2) = -2a+b ⇒ 10=-2a+b
                       __________  -
                       5 = 5a
                       a = 1

f(3) = 3a+b
15 = 3(1) + b
b = 13-3
b = 12

f(x) = x + 12

f(7) = 7 + 12 = 5

Answer 2

15 = 3a + b
10 = - 2a+b  _
 5 = 5a
 1 = a
subtitusikan
f(3) = 3a+b
15 = 3(1) + b
b = 13-3
b = 12
rumus fungsi
f(x) = x + 12
hasil f(7)
f(7) = 7 + 12 = 5