若2x+3y=2011,则2(3x-2y)-(x-y)+(-x+9y)=?
问题描述:
若2x+3y=2011,则2(3x-2y)-(x-y)+(-x+9y)=?
答
2(3x-2y)-(x-y)+(-x+9y)
=6x-4y-x+y-x+9y
=4x+6y
=2(2x+3y)
=2×2011
=4022