a*b=a+(a+1)+(a+2)+.+(a+b-1) 95*b=585 b=?
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![a*b=a+(a+1)+(a+2)+.+(a+b-1) 95*b=585 b=?](/uploads/image/z/5433552-0-2.jpg?t=a%2Ab%3Da%2B%28a%2B1%29%2B%28a%2B2%29%2B.%2B%28a%2Bb-1%29+95%2Ab%3D585+b%3D%3F)
a*b=a+(a+1)+(a+2)+.+(a+b-1) 95*b=585 b=?
a*b=a+(a+1)+(a+2)+.+(a+b-1) 95*b=585 b=?
a*b=a+(a+1)+(a+2)+.+(a+b-1) 95*b=585 b=?
a*b=a+a+1+……+(a+b-1)=ab+b(b-1)/2 把a=95代入,得 95b+b(b-1)/2=585 b^+189b-1170=0 (b-6)(b+195)=0 b=6或b=-195(舍去) 故b=6
采纳哦