(-y+5+4y^2)-(-y^2+5y-4),其中y=-2

问题描述:

(-y+5+4y^2)-(-y^2+5y-4),其中y=-2

(-y+5+4y2)-(-y2+5y-4)
=-y+5+4y2+y2-5y+4
=5y2-6y+9
=20+12+9
=41