(1)矩形的周长是28cm,两边长为x,y,且x^3+x^2*y-xy^2-y^3=0,求矩形的面积.(2)3x^(2m+3)+75x
问题描述:
(1)矩形的周长是28cm,两边长为x,y,且x^3+x^2*y-xy^2-y^3=0,求矩形的面积.(2)3x^(2m+3)+75x
答
X^3+X^2Y-XY^2-Y^3=0 X^2(X+Y)-Y^2(X+Y)=0 (X^2-Y^2)(X+Y)=0 (X-Y)(X+Y)^2=0 X=Y 该矩形是正方形 边长:28÷4=7cm 面积:7*7=49cm^2