问题
填空题
一个矩形的面积是3(x2-y2),如果它的一边长为(x+y),则它的周长是______.
答案
3(x2-y2)÷(x+y),
=3(x+y)(x-y)÷(x+y),
=3(x-y),
周长=2[3(x-y)+(x+y)],
=2(3x-3y+x+y),
=2(4x-2y),
=8x-4y.
所以它的周长是:8x-4y.
一个矩形的面积是3(x2-y2),如果它的一边长为(x+y),则它的周长是______.
3(x2-y2)÷(x+y),
=3(x+y)(x-y)÷(x+y),
=3(x-y),
周长=2[3(x-y)+(x+y)],
=2(3x-3y+x+y),
=2(4x-2y),
=8x-4y.
所以它的周长是:8x-4y.