diketahui f(x)=6-3x jika f(a)=-15, nilai a adalah

f(x) = 6-3x
f(a) = -15
Dit : nilai a ..?

f(a) = 6 - 3(a)
-15 = 6 - 3a
3a = 6 + 15
3a = 21
a = 21/3 = 7

f(x) = 6-3x
f(a) = -15
tinggal di substitusikan
-15 = 6 - 3a
3a = 6 + 15
3a = 21
a = 21/3
a = 7