当x=何值时,代数式x^2一4/x^2十3x与x^2一9/x^2一4x十4的值互为倒数

问题描述:

当x=何值时,代数式x^2一4/x^2十3x与x^2一9/x^2一4x十4的值互为倒数

(x^2一4)/(x^2十3x)*(x^2一9)/(x^2一4x十4)=1
[(x-2)(x+2)]/[x(x+3)]*[(x-3)(x+3) ]/(x-2)^2=1[(x+2)(x-3)]/[x(x-2)]=1x^2-x-6=x^2-2x x=6