2x²+(4y-7)x+2y²-7y+3=2x²+4xy+2y²-7x-7y+3=2(x²+2xy+y²)-7(x+y)+3=2(x+y)²-7(x+y)+3=[2(x+y)-1][(x+y)-3]=(2x+2y-1)(x+y-3)