(1)=x²(x-3)-(x-3)
=(x²-1)(x-3)
=(x-1)(x+1)(x-3)
(2) =(2x+4y)²-(3x-3y)²
=(2x+4y-3x+3y)(2x+4y+3x-3y)
=(7y-x)(5x+y)