Diketahui f(x)= (x-4)(2x-1) dan f'(p)=15. Nilai f(p)= A.22 B. 15 C.8 D.6 E.2 Mohon bantuannya serta caranya

f(x) = (x-4)(2x-1)
u = x-4 , u' = 1
v = 2x-1 , v' = 2

f'(x) = u'v + uv'
= (1)(2x-1) + (x-4)(2)
= 2x-1 + 2x-8
= 4x-9
f'(p) = 4p-9
15 = 4p-9
24 = 4p
p = 6

Maka: f(p) = (p-4)(2p-1)
= (6-4)(6×2-1)
= 2(12-1)
= 22