热心网友
回答时间:2025-01-13 17:46
4/( X²-4)+1/(X+2)
=4/(X+2)(X-2)+1/(X+2)
=4/(X+2)(X-2)+(X-2)/(X+2)(X-2)
=[4+(X-2)]/(X+2)(X-2)
=(X+2)/(X+2)(X-2)
=1/(X+2)
1/(X+1)-1/(X-1)
=(X-1)/(X+1)(X-1)-(X+1)/(X+1)(X-1)
=[(X-1))-(X+1)]/(X+1)(X-1)
=-2/(X²-1)
X+1-X²/(X-1 )
=(X+1)(X-1 )/(X-1 )-X²/(X-1 )
=(X²-1)/(X-1 )-X²/(X-1 )
=[(X²-1)-X²]/(X-1 )
=-1/(X-1 )
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