急!急!请教几道初中分式题,谢谢
1,(M^2-3M+2)/(M^2+2M-3)
=(M-1)(M-2)/((M-1)(M+3))
=(M-2)/(M+3)
2,((M^2-M-6)/(M-3))/((M+3)/(M^2+M-6))
=((M+2)(M-3)/(M-3))/((M+3)/(M-2)(M+3))
=(M+2)/(1/(M-2))
=(M+2)*(M-2)
=M^2-4 (M=1/M=>M^2=1)
=1-4
=-3
3,(X-2Y)^2=0 =>X-2Y=0 =>X=2Y
(X-Y)/(X+Y)
=(2Y-Y)/(2Y+Y)
=Y/3Y
=1/3
4,X=√3-4
4-X
---------- ...全部
1,(M^2-3M+2)/(M^2+2M-3)
=(M-1)(M-2)/((M-1)(M+3))
=(M-2)/(M+3)
2,((M^2-M-6)/(M-3))/((M+3)/(M^2+M-6))
=((M+2)(M-3)/(M-3))/((M+3)/(M-2)(M+3))
=(M+2)/(1/(M-2))
=(M+2)*(M-2)
=M^2-4 (M=1/M=>M^2=1)
=1-4
=-3
3,(X-2Y)^2=0 =>X-2Y=0 =>X=2Y
(X-Y)/(X+Y)
=(2Y-Y)/(2Y+Y)
=Y/3Y
=1/3
4,X=√3-4
4-X
---------- (分子分母同时乘以X-2)
X-2 4-X 4-X 4-X
--------------= -------------=----------=-------
12 X^2-4-12 X^2-16
X+2- ------ (X+2)(X-2)-12
X-2
4-X -1 -1 √3
=-----------=--------= --------= - -----
(X-4)(X+4) (X+4) √3-4+4 3。
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