Question

若3x+5 A B ------------=------- + -------,求A,B的值(要有过程)(x+2)(x

Answer 1

(3x+5)/(x+2)(x+3)=A/(x+2)+B/(x+3)

(3x+5)/(x+2)(x+3)=[A(x+3)+B(x+2)]/[(x+2)(x+3)]

所以3x+5=A(x+3)+B(x+2)=(A+B)x+(3A+2B)

所以3=A+B,3A+2B=5

2A+2B=6

3A+2B=5

A=-1

B=3-A=4