Question

Cho \(\left(x+2\right)f\left(x+1\right)=\left(x+1\right)f\left(x+3\right)\),tính f(5)

Answer 1

Ta có:

Với x = -2 

=> \(0.f\left(-2+1\right)=\left(-2+1\right).f\left(-2+3\right)\)

=> \(f\left(1\right)=0\) (1)

Với x = 0

=> \(2.f\left(1\right)=1.f\left(3\right)\) (2)

(1) ; (2) => \(f\left(3\right)=0\)(3)

Với  x = 2

=> \(4.f\left(3\right)=3.f\left(5\right)\)(4)

Từ (3) ; (4) => f ( 5 ) = 0.

Answer 2

Link ảnh: https://imgur.com/7VWoyPW