4x+4xy-3y+4x+10y-3=(2x+y)^2-4y^2+4x+10y-3 =(2x+y)^2+2(2x+y)-(4y^2-10y+3) =(2x+y)^2+2(2x+y)-(2y-1)(2y-3) =(2x+y+2y-1)(2x+y-2y+3) =(2x+3y-1)(2x-y+3)