1.计算：（-2-x)(2-x)-(x-2)² 2.计算：(x-2y+4)(x-2y-4) 3.(2a-b+3c)눀 注！！！下面还有题目

1.计算：（-2-x)(2-x)-(x-2)²
=(x+2)(x-2)-(x-2)²
=(x-2)(x+2-x+2)
=4(x-2)
=4x-8

2.计算：(x-2y+4)(x-2y-4)
=(x-2y)²-16
=x²-4xy+4y²-16

3.(2a-b+3c)²
=4a²+b²+9c²-4ab-6bc+12ac

4.利用平方差计算：30.1*29.9
=(30+0.1)(30-0.1)
=900-0.01
=899.99

5.分解因式：9x³y-4xy³
=xy(9x²-4y²)
=xy(3x+2y)(3x-2y)

6.分解因式：3ax²-18ax+15a
=3a(x²-6x+5)
=3a(x-5)(x-1)

7.分解因式：a²(3a-2)+(2-3a)b²
=(3a-2)(a²-b²)
=(3a-2)(a+b)(a-b)

8.分解因式：4x²-4xy+y²-16z²
=(2x-y)²-16z²
=(2x-y+4z)(2x-y-4z)

9.分解因式：3(x+y)(x-y)-（x-y)²
=(x-y)(3x+3y-x+y)
=(x-y)(2x+4y)
=2(x-y)(x+2y)

10.分解因式：(x²-2x²)-11(x²-2x)+24
=(x²-2x-3)(x²-2x-8)
=(x-3)(x+1)(x-4)(x+2)