(-x+4y+z)(-x+4y-z)=___x²-8xy+16y²-z²____ (3a-1)(__3a-1_____)=1-6a+9a² (-x-y)·(x-y)=-x²-2xy-y²______ 4x²+9y²=(2x+3y)² - __12xy_____=(2x-3y)²+__12xy______. (x+1)²(x-1)²(x²+1)²=_x^8-2x^4+1_______ (x+y)²·(x²-2xy+y²)=__x^4-2x²y²+y_^4______