1.x^4+x^2+2ax+1-a^2 = x^4+2x^2+1 -(x^2-2ax+a^2)=(x^2+1)^2-(x-a)^2=(x^2+x+a+1)(x^2-x-a+1) 2.4x^2-4x-y^2+4y-3=4x2-4x+1-(y^2-4y+4)=(2x-1)^2 - (y-2)^2 = (2x+y-3)(2x-y+1)3.x^4-7x^2+1=x^4 - 2x^2 + 1 - 9x^2 ...