2x^2-3xy+(-y^2)-2x^2-(-5xy)+2y^2=?
问题描述:
2x^2-3xy+(-y^2)-2x^2-(-5xy)+2y^2=?
答
2x^2-3xy+(-y^2)-2x^2-(-5xy)+2y^2
=-3xy-y²+5xy+2y²
=y²+2xy
=y(y+2x)
答
=2X^2-3XY-Y^2-2X^2+5XY+2Y^2
=Y^2+2XY