yxy的精選

問題詳情：先化簡,再求值:(2x+y)2+(x-y)(x+y)-5x(x-y),其中.【回答】解:(2x+y)2+(x-y)(x+y)-5x(x-y)=4x2+4xy+y2+x2-y2-5x2+5xy=9xy,當x=+1,y=-1時,原式=9×(+1)×(-1)=9×(2-1)=9×1=9.知識點：乘法公式題型：解答題...

問題詳情：把多項式x2y﹣2xy2+y3分解因式，正確的結果是（）  A．y(x﹣y)2     B．y(x+y)(x﹣y)     C．y(x+y)2   D．y(x2﹣2xy+y2)【回答】A   知識點：因式分解題型：選擇題...