f(x) = 7x-9 lalu nilai f(a) = 12. Maka brp kah Nilai A (pakai cara ya)

Diketahui : f (x)=7x-9
Ditanya : nilai A
Substitusikan a ke x, maka
f (a) = 7a-9 = 12
= 7a = 12+9
= 7a = 21
= a = 3

f(x) = 7x - 9
f(a) = 12
12 = 7a - 9
21 = 7a
3 = a

maaf kalau salah, semoga membantu