3x(x-2y)+(x+2y)(2x-y)-3y(y-2x)
=3x(x-2y)+ (x+2y)(2x-y)+3y(2x-y)
=3x(x-2y)+ (x+2y+3y)(2x-y)
=3x(x-2y)+ (x+5y)(2x-y)
= 3x²-6xy + 2x²-5y²+10xy -xy
= 5x² +3xy -5y²
3x(x-2y)+(x+2y)(2x-y)-3y(y-2x)
=3x(x-2y)+ (x+2y)(2x-y)+3y(2x-y)
=3x(x-2y)+ (x+2y+3y)(2x-y)
=3x(x-2y)+ (x+5y)(2x-y)
= 3x²-6xy + 2x²-5y²+10xy -xy
= 5x² +3xy -5y²