shu/xue数学、(要算式和结果)
某操场宽为xm,长比宽多5m,若将操场的长宽分别加长5m时,这个操场的面积将增加200m的平方,那么这个操场原来的长和宽各是多少米?
(x的平方+ax+b)(2x的平方-3x-1)
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当x取何值时,代数式6(x+2)(x-3)与(3x-1)(2x+1)的差小于7?
解方程:(x-3)(x-2)+18=(x+9)(x+1)
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解方程:(x-6)(x的平方+x+1)-x(x+1)(x-1)=x(2-5x)
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(xy)(x-2y)-(3x-2y)(x-3y),其中x=4,y=-1
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(x+1)(x的平方-x+1)
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