(1)(x+z)²-(x+z)²
=(x+z+x+z)(x+z-x-z)
=(x+z+x+z)(0)
=0
(2)4a²+4ab+b²
=(2a+b)²
(3)x²-6x+9
=(x-3)²
(4)-9x²+12xy-4y²
=-(3x-2y)²
(5)a²+ab+0.25b²
=(a+0.5)²
(6)(2a+b)²-8(2a+b)+16
=(2a+b-4)²
(7)a⁴-81b⁴
=(a²+9b²)(a²-9b²)
=(a²+9b²)(a+3b)(a-3b)
(8)27a³bc-3ab³c
=3abc(9a²-3b²)
=3abc(3a+√3b)(3a-√3b)
最后的那一题看不清楚题目