Question

先化简再求值x+2分之x的平方+2x+1除以x-1分之x的平方

Answer 1

x+1分散孝之1-1-x)除以x 的平方-1分之1
=（1-（x+1）²）链掘贺/(x+1)×(x+1)(x-1)
=(-x²-2x)(x-1)
=-x(x-1)(x+2)
=-1/棚派2×(1/2-1)×(1/2+2)
=-1/2×(-1/2)×(5/2)
=5/8;