2x+3y=2012,则代数式2(3x-2y)-(x-y)+(-x+9y)=(?)

问题描述:

2x+3y=2012,则代数式2(3x-2y)-(x-y)+(-x+9y)=(?)

2(3x-2y)-(x-y)+(-x+9y)
=6x-4y-x+y-x+9y
=4x+6y
=2(2x+3y)
=2×2012
=4024