Question

Suatu fungsi ditentukan f(x) = 5x-4
a.tentukan nilai f(-4) dan f(5) !
b. tentukan nilai a jika f(a)=-34

Answer 1

F(-4) = 5.(-4) - 4
= -20 - 4
= -24

f (5) = 5.5-4
= 25-4
= 21

f (a) = -34
-34 = 5x-4
-34 + 4 = 5x
-30 = 5x
-30/5 = x
-6 = x

jadi, a adalah -6

Answer 2

F(-4)
f (x) = ax + b
f (-4) = 5(-4) -4
        = -20 -4
f (5) = 5(5) -4
     = 25 - 4
nilai a jika f(x) = -34
                f(x) = 5(x)-4 = -34
                34 -  4 = 30.
                 30 : 5 = 6
b. 6