先化简再求值
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先化简再求值
先化简再求值
先化简再求值
给你上图,话说5分真心少啊,.自己写的,应该还算清晰明了
原式=X/(X+2)-(X+1)²/(X+2)÷(X+1)(X-1)/(X-1)
=X/(X+2)-(X+1)²/(X+2)÷(X+1)
=X/(X+2)-(X+1)²/(X+2)*1/(X+1)
=X/(X+2)-(X+1)/(X+2)
=(X-X-1)/(X+2)
=-1/ (X+2)...
全部展开
原式=X/(X+2)-(X+1)²/(X+2)÷(X+1)(X-1)/(X-1)
=X/(X+2)-(X+1)²/(X+2)÷(X+1)
=X/(X+2)-(X+1)²/(X+2)*1/(X+1)
=X/(X+2)-(X+1)/(X+2)
=(X-X-1)/(X+2)
=-1/ (X+2)
把X=√3-2代入得
原式=-1/(√3-2+2)
=-1/√3
=-√3/3
收起
x/(x+2)-(x+1)(x+1)/(x+2)*(x-1)/(x+1)(x-1)=x/(x+2)-(x+1)/(x+2)=-1/(x+2),x=根号3-2带入,可得-根号3/3
= X / (X+2) - (X+1) / (X+2)
=-1/(X+2)
然后你自己将X带入就行了