Jika nilai Integral(dari 7 ke 9) f(x) dx = 16 dan Integral(dr 1 ke 4) f(2x-1) dx = 20, maka nilai integral(dr 1 ke 9) f(x) dx adalah … A. 16 B. 36 C. 40 D. 56E.

kalau menurut saya jawabanx c. 40

Int (7 - 9) f(x) dx = 16

Int (1 - 4) f(2x - 1) dx = 20
Misal u = 2x - 1 => du = 2 dx => dx = 1/2 du
x = 1 => u = 2(1) - 1 = 1
x = 4 => u = 2(4) - 1 = 7
Int (1 - 4) f(2x - 1) dx = 20
Int (1 - 7) f(u) 1/2 du = 20
Int (1 - 7) f(u) du = 40
Int (1 - 7) f(x) dx = 40

Int (1 - 9) f(x) dx = int (1 - 7) f(x) dx + int (7 - 9) f(x) dx
= 40 + 16
= 56