Question

计算下列题

9-x²之分x²-6x+9÷x²+3x分之2x-6=？ （xy-x²）²÷xy分之（x-y）²×x²分之x-y=? a²+2a-8分之a²-16÷（a－2）xa-2分之a²+4-4a

Answer 1

9-x²之分x²-6x+9÷x²+3x分之2x-6
=(9-x²)之分(x²-6x+9)÷(x²+3x)分之(2x-6)
=[(x²-6x+9)/(9-x²)]÷[(2x-6)/(x²+3x)]
={(x-3)²/[(3+x)(3-x)]}÷{2(x-3)/[x(x+3)]}
={(x-3)²/[-(3+x)(x-3)]}÷{2(x-3)/[x(x+3)]}
={-(x-3)/(3+x)}÷{2(x-3)/[x(x+3)]}
={-(x-3)/(3+x)}*{x(x+3)/[2(x-3)]}
=-1*{x/2}
= - x/2

（xy-x²）²÷xy分之（x-y）²*x²分之x-y
=(xy-x²)²÷[(x-y)²/xy]*[(x-y)/x²]
=[x(y-x)]²*[xy/(x-y)²]*[(x-y)/x²]
=[x²(y-x)²]*[xy/(x-y)²]*[(x-y)/x²]
=[xy]*[(x-y)]
=xy(x-y)

a²+2a-8分之a²-16÷（a－2）xa-2分之a²+4-4a
=(a²+2a-8)分之(a²-16)÷(a－2)*(a-2)分之(a²+4-4a)
=[(a²-16)/(a²+2a-8)]÷(a－2)*[(a²-4a+4)/(a-2)]
=[(a+4)(a-4)/(a-2)(a+4)]*[1/(a－2)]*[(a-2)²/(a-2)]
=[(a-4)]*[(1/(a-2)]
=(a-4)/(a-2)