3(m^2-mn+2n^2)-2(mn-m^2+n^2)+(5mn-4n^2+1)_数学解答

3(m^2-mn+2n^2)-2(mn-m^2+n^2)+(5mn-4n^2+1)

人气：336 ℃　时间：2020-03-23 21:22:29

解答

原式=3m^2-3mn+6n^2-2mn+2m^2-2n^2+5mn-4n^2+1
=5m^2+1（2x-3y+z)-3(x-2(-z+(x-y))-(3y-5z)原式=2x-3y+z-3(x+2z-2x+2y)-3y+5z=2x-6y+6z-3x-6z+6x-6y=5x-18y