①(-2x-1/3y)²=____②｛（-5+x）（-5-x）｝²=_____③（x+y+z)(x-y-z）=___.④若x²+y²快

①(-2x-1/3y)²=____②｛（-5+x）（-5-x）｝²=_____③（x+y+z)(x-y-z）=___.④若x²+y²快
①(-2x-1/3y)²=____②｛（-5+x）（-5-x）｝²=_____③（x+y+z)(x-y-z）=___.④若x²+y²
快

①(-2x-1/3y)²=____②｛（-5+x）（-5-x）｝²=_____③（x+y+z)(x-y-z）=___.④若x²+y²快
①(-2x-1/3y)²=4x²+4/3x+1/9y²
②｛（-5+x）（-5-x）｝²
=(25-x²)²
=625-50x²+x^4
③（x+y+z)(x-y-z）
=x²-(y+z)²
=x²-y²-z²-2yz