Question

分式加减题~

m-15/m²-9－2/3-m
（x-1－8/x+1)÷x+3/x-1
1/4x²-9y²÷(1/2x+3y－1/ 2x-3y)

Answer 1

m-15/m²-9－2/3-m =（m-15）/(m+3)(m-3) +2(m+3)/(m+3)(m-3)
=3(m-3)）/纯返(m+3)(m-3)=3/(m+3)
(x-1－磨裤枣8/x+1)÷x+3/x-1这个实在分辨不来 是瞎拆按此计算
[x-1-8/(x+1)]÷(x+3)/(x-1）
={[x(x+1)-(x+1)-8]/(x+1)}÷(x+3)/(x-1)=[(x+3)(x-3)/(x+1)]*(x-1)/(x+3)
=(x-3)(x-1)/(x+1)
1/4x²-9y²÷(1/2x+3y－1/ 2x-3y)=1/(4x²-9y²)÷[1/(2x+3y)-1/(2x-3y)]
=1/(2x+3y)(2x-3y)÷[(2x-3y)-(2x+3y)]/(2x+3y)(2x-3y)
=-1/6y

Answer 2

①(m-15)／(m²销亮-9)--2／(3-m)
=(m-15)／(m+3)(m-3)+2(m+3)／(m-3)(m+3)
=3(m-3)／(m+3)(m-3)
=3／(m+3)
②[(x-1)-8／(x+1)]÷[(x+3)／(x-1)]
=[(x²-9)／改斗游(x+1)]×[(x-1)／(x+3)]
=[(x+3)(x-3)／(x+1)]×[(x-1)／(x+3)]
=(x-3)(x-1)／(x+1)
③[1/(4x²-9y²)]÷[1/核销(2x+3y)－1/( 2x-3y)]
=[1／(2x+3y)(2x-3y)]÷[(2x-3y)／(2x+3y)(2x-3y)-(2x+3y)／(2x+3y)(2x-3y)]
=[1／(2x+3y)(2x-3y)]÷[(-6y)／(2x+3y)(2x-3y)]
=[1／(2x+3y)(2x-3y)]×[(2x+3y)(2x-3y)／(-6y)]
= -1／6y

Answer 3

m-15/m-9－2/3-m =（m-15）/(m+3)(m-3) +2(m+3)/(m+3)(m-3)
=3(m-3)）/(m+3)(m-3)=3/(m+3)
(x-1－8/x+1)÷x+3/x-1这个实在分辨不来 是按此计算
[x-1-8/(x+1)]÷(x+3)/(x-1）
={[x(x+1)-(x+1)-8]/(x+1)}÷(x+3)/(x-1)=[(x+3)(x-3)/(x+1)]*(x-1)/(x+3)
=(x-3)(x-1)/(x+1)
1/4x-9y÷(1/2x+3y－1/烂吵 2x-3y)=1/(4x-9y)÷[1/(2x+3y)-1/饥尺侍(2x-3y)]
=1/(2x+3y)(2x-3y)÷[(2x-3y)-(2x+3y)]/(2x+3y)(2x-3y)
=-1/6y
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