1.若­­1/a-1/b=3,分式(2a+3ab-2b)/(a-2ab-b)的值为__.2.x/2=y/3,分式(7x²-y²)/(x²-2xy+3y²)的值是?

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1.若­­1/a-1/b=3,分式(2a+3ab-2b)/(a-2ab-b)的值为__.2.x/2=y/3,分式(7x²-y²)/(x²-2xy+3y&s

1.若­­1/a-1/b=3,分式(2a+3ab-2b)/(a-2ab-b)的值为__.2.x/2=y/3,分式(7x²-y²)/(x²-2xy+3y²)的值是?
1.若­­1/a-1/b=3,分式(2a+3ab-2b)/(a-2ab-b)的值为__.
2.x/2=y/3,分式(7x²-y²)/(x²-2xy+3y²)的值是?

1.若­­1/a-1/b=3,分式(2a+3ab-2b)/(a-2ab-b)的值为__.2.x/2=y/3,分式(7x²-y²)/(x²-2xy+3y²)的值是?
1.若1/a-1/b=3,分式(2a+3ab-2b)/(a-2ab-b)的值为_3/5_.
(2a+3ab-2b)/(a-2ab-b)上下同除以ab
(2/b+3-2/a)/(1/b-2-1/a)=-3/(-5)=3/5
2.x/2=y/3,分式(7x²-y²)/(x²-2xy+3y²)的值是?(要过程)
x/2=y/3,则x/y=2/3
(7x²-y²)/(x²-2xy+3y²)上下同除以y²,(7 x²/ y²-1)/ (x²/ y²-2x/y+3)=(7*4/9-1)/(4/9-2*2/3+3)=19/19 =1

1、由题(b-a)/ab=3
a-b=-3ab
原式=[2(a-b)+3ab]/[(a-b)-2ab]=(-3ab)/(-5ab)=3/5
2、x/y=2/3
设x=2k,则y=3k
原式=(28k2-9k2)/(4k2-12k2+27k2)=1

1.3ab=b-a代入得(a-b)/(a-b-2/3b+2/3a)=3/5

1.3/5
1/a-1/b=3=>(b-a)/ab=3=>ab=(b-a)/3所以(2a+3ab-2b)/(a-2ab-b)=(a-b)/5/3(a-b)=3/5
2.1
x=2/3y
7*(2/3y)2-y2/(2/3y)2-2*2/3y*y+3y2=(28/9-1)/(4/9-4/3+3)=1

1.化简1/a-1/b=3 得b-a=3ab
代入式子得(2a+3ab-2b)/(a-2ab-b)=[3ab-2(b-a)]/[-2ab-(b-a)]=(3ab-6ab)/(-2ab-3ab)=3/5
2.由已知,得y=3x/2
所以7x²-y²=7x²-9x²/4=19x²/4;
x²-2xy+3y&s...

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1.化简1/a-1/b=3 得b-a=3ab
代入式子得(2a+3ab-2b)/(a-2ab-b)=[3ab-2(b-a)]/[-2ab-(b-a)]=(3ab-6ab)/(-2ab-3ab)=3/5
2.由已知,得y=3x/2
所以7x²-y²=7x²-9x²/4=19x²/4;
x²-2xy+3y²=x²-3x²+27x²/4=19x²/4
所以(7x²-y²)/(x²-2xy+3y²)=1

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