Question

-y^2+2xy-x^2+3x-3y

Answer 1

-y^2 +2xy - x^2 +3x-3y

=-( y^2-2xy+x^2) +3 (x-y)

= - (y-x)^2 +3(x-y)

=-(x-y)^2 +3(x-y)

=> (x-y) (3- x+y)

Answer 2

-y^2+2xy-x^2+3x-3y

=-x^2+2xy-y^2+3x-3y

=-(x^2-2xy+y^2)+3(x-y)

=-(x-y)^2+3(x-y)

=3(x-y)-(x-y)^2

=(x-y)(3-x+y)