3x^2-xy/9x^2-6xy+y^2,其中x=-8,y=2.

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紫璞720504 共回答了23个问题 | 采纳率87%: (3x²-xy)/(9x²-6xy+y²)
=x(3x-y)/(3x-y)²
=x/(3x-y)
=-8/(-24-2)
=4/13; 1年前

xuexue1111 共回答了15个问题 | 采纳率86.7%: 冬季天气干燥，人们在滋润和保护皮肤时，往往看中的是品牌和价位，但是，商场各化妆品专柜动辄上千元的保养品，却又让人望而却步。; 1年前

求分式方程和分式乘法答案,1.分别求下列各个分式当x=4,y=5时的值3x^2-xy/9x^2-6xy+y2x^2-4y 求分式方程和分式乘法答案, 1.分别求下列各个分式当x=4,y=5时的值 3x^2-xy/9x^2-6xy+y2 x^2-4y^2/x^2-4xy+4y^2 2.计算 4x^2-y^2/3x^2y除以2x-y/xy a+b/a^2-b^2*a^2-2ab+b^2/ab 3,化简 -9x^2+4y^2/9x^2+12xy+4y^2 a-ab/b^2-2b+1 求值,当x=3,y=7时,求分式x^2-4/(xy+2y)-(x+2)的值 计算 x^4-1/x^2+2x+1除以(x^2+1) fz92741年前3: kaokao321 共回答了17个问题 | 采纳率88.2%

1.分别求下列各个分式当x=4,y=5时的值
3x^2-xy/9x^2-6xy+y2
=x(3x-y)(3x-y)^2
=x/(3x-y)
=4/(12-5)
=4/7
x^2-4y^2/x^2-4xy+4y^2
=(x+2y)(x-2y)/(x-2y)^2
=(x+2y)/(x-2y)
=(4+10)/(4-10)
=-7/3
2.计算
(4x^2-y^2/3x^2y)/(2x-y/xy)
=[(2x-y)(2x+y)xy]/[(2x-y)3x^2y]
=(2x+y)/3x
a+b/a^2-b^2*a^2-2ab+b^2/ab
=[(a+b)/(a+b)(a-b)]*[(a-b)^2/ab]
=(a-b)/ab
3,化简
-9x^2+4y^2/9x^2+12xy+4y^2
=[(2y-3x)(2y+3x)]/(2y+3x)^2
=(2y-3x)/(2y+3x)
a-ab/b^2-2b+1
=a(1-b)/(1-b)^2
=a/(1-b)
求值,当x=3,y=7时,求分式x^2-4/(xy+2y)-(x+2)的值
(x^2-4)/[(xy+2y)-(x+2)]
=[(x+2)(x-2)]/[y(x+2)-(x+2)]
=[(x+2)(x-2)]/[(y-1)(x+2)]
=(x-2)/(y-1)
=(3-2)/(7-1)
=1/6
计算
x^4-1/x^2+2x+1除以(x^2+1)
(x^4-1)/(x^2+2x+1)
=(x^2+1)(x^2-1)/(x+1)^2
=(x^2+1)(x+1)(x-1)/(x+1)^2
=(x^2+1)(x-1)/(x+1)

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