Diketahui fungsi f(x) = 5x – 8. Jika f(-2) = a dan f(b) = 22, nilai a + b adalah . . .

f(x) = 5x - 8
f(-2) = a
f(b) = 22
a+b =...

Jwb:
<=> f(-2)= 5x - 8
a = 5(-2) - 8
a = - 10 - 8
a = - 18
<=> f(b)= 5x - 8
22= 5(b) - 8
22+8= 5b
30= 5b
b = 6
<=> a+b = - 18 + 6 = - 12