Question

解方程:x+1分之2x平方-x平方分之3x+3=-5

Answer 1

2x²/(x+1)-3(x+1)/x²=-5

令a=x²/(x+1)

2a-3/a=-5

2a²+5a-3=0

(2a-1)(a+3)=0

a=1/2,a=-3

x²/(x+1)=1/2

2x²-x-1=0

(2x+1)(x-1)=0

x=-1/2,x=1

x²/(x+1)=-3

x²+3x+3=0

无解

所以x=-1/2,x=1