1、计算(1)2/m+1/m (2)3b/xy-b/xy (3)(a/a+b)+b/a+b (4)(5x/2x-y)-x+2y/2x-y 2、计算:(1)2/-mn+10/mn (2)(2/x-1)-3/1-x(3)(x+3/x+1)-(x-1/x+1)+x-2/x+1 (4)(t+4k/9k²-4t²)+k-t/4t²-9k&
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1、计算(1)2/m+1/m (2)3b/xy-b/xy (3)(a/a+b)+b/a+b (4)(5x/2x-y)-x+2y/2x-y 2、计算:(1)2/-mn+10/mn (2)(2/x-1)-3/1-x(3)(x+3/x+1)-(x-1/x+1)+x-2/x+1 (4)(t+4k/9k²-4t²)+k-t/4t²-9k&
1、计算
(1)2/m+1/m (2)3b/xy-b/xy (3)(a/a+b)+b/a+b (4)(5x/2x-y)-x+2y/2x-y
2、计算:
(1)2/-mn+10/mn (2)(2/x-1)-3/1-x
(3)(x+3/x+1)-(x-1/x+1)+x-2/x+1 (4)(t+4k/9k²-4t²)+k-t/4t²-9k²
注明:这里的/都表示分数线,每题至少2部.
3、先化简,再求值:y平方/y-2+4/2-y,其中y=-9/2
1、计算(1)2/m+1/m (2)3b/xy-b/xy (3)(a/a+b)+b/a+b (4)(5x/2x-y)-x+2y/2x-y 2、计算:(1)2/-mn+10/mn (2)(2/x-1)-3/1-x(3)(x+3/x+1)-(x-1/x+1)+x-2/x+1 (4)(t+4k/9k²-4t²)+k-t/4t²-9k&
(1)2/m+1/m =(2+1)/m=3/m
(2)3b/xy-b/xy=(3b-b)/xy=2b/xy
(3)(a/a+b)+b/a+b=(a+b)/(a+b)=1
(4)(5x/2x-y)-x+2y/2x-y=(5x-x-2y)/(2x-y)=(4x-2y)/(2x-y)=2(2x-y)/(2x-y)=2
(1)2/-mn+10/mn =(-2+10)/mn=8/mn
(2)(2/x-1)-3/1-x=2/(x-1)+3/(x-1)=(2+3)/(x-1)=5/(x-1)
(3)(x+3/x+1)-(x-1/x+1)+x-2/x+1=(x+3-x+1+x-2)/(x+1)=(x+2)/(x+1)
(4)(t+4k/9k²-4t²)+k-t/4t²-9k²
=(t+4k)/(9k²-4t²)+(t-k)/(9k²-4t²)
=(t+4k+t-k)/(9k²-4t²)
=(2t+3k)/(3k-2t)(3k+2t)
=1/(3k-2t)