F.3 Exercise on Factorization (20 marks)

1.-5x -45x
= -5x(x+9)
2.x+8x-9
= (x+9)(x-1)
3.-2x-18x
= -2x(x+9)
4.3x+36x+81
= 3(x+3)(x+9)
5.8x+104x+288
= 8(x+4)(x+9)
6.-x-7x+18
= (x+9)(2-x)
7.-3x-39x-108
= -3(x+4)(x+9)
8.-3x-9x+162
= -3(x+9)(x-6)
9.2x+30x+108
= 2(x+6)(x+9)
10.4x+72x+324
= 4(x+9)
11.-7x-91-252
= -7(x+9)(x+4)
12.-8x-24x+632
= -8[x(x+3)-79]
13.-4x-32x+36
= -4(x-1)(x+9)
14.6x+0x-486
= 6(x-9)
15.x+14x+45
= (x+5)(x+9)
16.4x+64x+252
= 4(x+7)(x+9)
17.5x+20x-225
= 5(x-5)(x+9)
18.-4x+ -48x-108
= -4(x+9)(x+3)
19.-2x-38x-180
= -2(x+10)(x+9)
20.x+13x+36
= (x+4)(x+9)

1.-5x -45x
= -5x (x+9)//

2.x+8x-9
= (x-1)(x+9)//

3.-2x-18x
= -2x(x+9)//

4.3x+36x+81
= 3(x+3)(x+9)//

5.8x+104x+288
= 8(x+4)(x+9)//

6.-x-7x+18
= -(x+9)(x-2)//

7.-3x-39x-108
= -3(x+4)(x+9)//

8.-3x-9x+162
= -3(x-9)(x+6)//

9.2x+30x+108
= 2(x+9)(x+6)//

10.4x+72x+324
= 4(x+9)//

11.-7x-91-252
= -7(x+4)(x+9)//

12.-8x-24x+632
= -8(x+3x-79)//

13.-4x-32x+36
= -4(x-9)(x+1)//

14.6x+0x-486
= 6(x - 81)
= 6(x-9)(x+9)//

15.x+14x+45
= (x+9)(x+5)//

16.4x+64x+252
= 4(x+7)(x+9)//

17.5x+20x-225
= 5(x+9)(x-5)//

18.-4x+-48x-108
係咪打錯...
如果係-48x...
= -4(x+3)(x+9)//
如果係 +48x
= -4(x-3)(x-9)//

19.-2x-38x-180
= -2(x+10)(x+9)//

20.x+13x+36
= (x+4)(x+9)//

用fx-3650 or 3690 計算機的話，
可down 一些cross method的programme...