[1] 9(a-b)^2+12(a-b)+a [2] 4(x-2)-(x+2)(x-2)

[1] 9(a-b)^2+12(a-b)+a [2] 4(x-2)-(x+2)(x-2)
[1] 9(a-b)^2+12(a-b)+a [2] 4(x-2)-(x+2)(x-2)

[1] 9(a-b)^2+12(a-b)+a [2] 4(x-2)-(x+2)(x-2)
是分解因式,还是整式乘法
[1] 9(a-b)²+12(a-b)+a
=9²-18ab+b²+12a-12b+a
=9²-18ab+b²+13a-12b
[2] 4(x-2)-(x+2)(x-2)
=4x-8-x²+4
=-x²+4x-4
=-(x²-4x+4)
=-(x-2)²