已知;3X-5/X2-2X-3=A/X-3+B/X+1則A=______,B=______
題目:
已知;3X-5/X2-2X-3=A/X-3+B/X+1則A=______,B=______
解答:
(3X-5)/(X^2-2X-3)=(3x-5)/[(x-3)(x+1)]
(3X-5)/(X2-2X-3)=A/(X-3)+B/(X+1)=[A(x+1)+B(x-3)]/[(x-3)(x+1)]
=[(A+B)x+(A-3B)]/(x^2-2x-3)
A+B=3
A-3B=-5
A=1 B=2
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