tolong jawab ya bantu saya

7. A
9. f(x) = 3 - 2x
f(a) = 15
15 = 3 - 2a
2a = 3 - 15
a = -12/2
a = -6
jadi nilai a yang memenuhi adalah a. -6

10. f(x) = ax + b
f(-2) = -2a + b = -1
f(-1) = -a+ b = 2

-2a + b = -1
-a + b = 2 (dikurangi)
-a = -3
a= 3

a= 3 maka
-2.3 + b = -1
-6+ b = -1
b = -1 +6
b = 5

nilai a + b = 3 + 5 = 8

12. f(2) + g(-1) = (2 -9) + ((-1) + 2)
= (-7) + 1
= -6