tolong bantu saya mengerjakan pr: please yg bener

2. f(x)= x- 1
f(-6) = -6-1=-7
f(-3)=-3-1=-4
f(0) = 0-1 = -1
f(3) = 3-1=2
f(6)=6-1=5
3. h(5)= -5+3 = -2
4. f(a) = 4- 3a = 25
-3a = 25 - 4
-3a = 21
a = -7

9. 5x + 3y = 1|×3
3x - 4y = -11|×5

15x + 9y = 3
15x - 20y = -55
____________ _
29y = 58
y = 2
5x +3(2) = 1
5x = 1-6
x = -1
maka x-y
-1-2 = -3