cuocuo119
幼苗
共回答了14个问题采纳率:78.6% 举报
答:
(8x+9)/(x^2+x-6)=a/(x+3)+b/(x-2)
(8x+9)/[(x+3)(x-2)] =a/(x+3)+b/(x-2)
两边同时乘以(x+3)(x-2)得:
8x+9=a(x-2)+b(x+3)
8x+9=(a+b)x+3b-2a
所以:
b+a=8…………(1)
3b-2a=9…………(2)
(1)*2+(2)得:
2b+3b=16+9
b=5
代入(1)解得:a=3
所以:a=3,b=5
1年前
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