计算[(x+2y)²-(2x-y)²]÷(3x+y)=

问题描述:

计算[(x+2y)²-(2x-y)²]÷(3x+y)=

[(x+2y)²-(2x-y)²]÷(3x+y)
=[(x+2y+2x-y)(x+2y-2x+y)]÷(3x+y)
=[(3x+y)(-x+3y)]]÷(3x+y)
=-x+3y