计算:a²-b²分之a²-2ab+b²÷(a分之1-b分之1)2.化简并求值:(x-y分之1+x+y分之1)÷x²-y²分之2x-y,其中x,y满足|x-2|+(2x-y-3)²=0
问题描述:
计算:a²-b²分之a²-2ab+b²÷(a分之1-b分之1)
2.化简并求值:(x-y分之1+x+y分之1)÷x²-y²分之2x-y,其中x,y满足|x-2|+(2x-y-3)²=0
答
原式=a²-b²分之(a-b)²÷ab分之(b+a)
=(a-b)(a+b)分之(a-b)²×(a+b)分之ab
=(a-b)(a+b)²分之(a-b)²×ab
=(a+b)分之ab(a-b)
2.原式=[(x-y)(x+y)分之(x+y)+(x-y)][(2x-y)分之(x-y)(x+y)]
=(2x-y)分之2x
由x-2|+(2x-y-3)²=0得x=2,y=1
∴(2x-y)分之2x=(2×2-1)分之2×2=3分之4