f fungsi. f (x) = ax+b, f (3) = -11, f (-2)= f. Nilai f (7) adalah?

jawab

f(x) = ax + b

f(3) =11 --> 3a + b = 11
f(-2) = 14 --> -2a + b = 14 .....kurangkan
5a= 25
a= 5

3a + b = 11
3(5) + b = 11
b =  11 - 15
b = - 4

f(x) = ax + b 
f(x)= 5x - 4

f(7)  = 5(7) - 4
f(7) = 31