fungsi f dinyatakan dgn rumus f (×)=ax+b jika f(2)=3 dan f (-3)=13 nilai -a+b adalah

3a+b=2
13a+b=-3
a=-1/2
b=3 1/2
-a+b= 4

f(x) = ax+b
f(2) = a(2)+b
3 = 2a+b

f(-3) = a(-3)+b
13 = -3a+b

13 = -3a+b
3. = 2a+b _
----------------
10 = -5a
-2 = a

13 = -3(-2) + b
13 = 6 + b
13 - 6 = b
7 = b

-a + b
= -(-2) + 7
= 2 + 7
= 9