diketahui rumus fungsi f(x) = 7 - 2x, jika f(a) = 9, nilai dari a - 5 adalah...

f(×)=7-2×
9 =7-2.9
=7-18
=-11

jadi a - 5 = -11-5=-16

Jawab :

f(a) = 7 - 2a
9 = 7 - 2a
9 - 7 = 2a
2 = 2a
a = 1

a - 5 = 1 - 5 = -4