我想問下d數學點做

1.(8X)(-3XX 6)
=(8X)(9X 6)
=72X 48X

2.(9XX-3)(5XX)
=(9X-3)(5X)
=45X

3.(-9X0(11XX 2)
=0X(11X 2)
=0

4.(7XX)(2X-9)
=(7X)(2X-9)
=14X-63X

5.(X 3)(X 2)
=X 3X 2X 6
=X 5X 6

6.(X-4)(X 5)
=X 5X-4X-20
=X X-20

7.(x 6)(X-1)
=X-X 6X-6
=X 5X-6

8.(3-X)(2-X)
=6-3X-2X X
=6-5X X

9.(1-X)(-X-2)
=-X-2 X 2X
=X-2 X

10.(-3-X)(-1 X)
=3-3X X-X
=3-2X-X

11.(2X 3)( 3X 1)
=6X 2X 9X 3
=6X 11X 3

12.(5X-4)(X 2)
=5X 10X-4X-8
=5X 6X-8

13.(3X 4)(4X-3)
=12X-9X 16X-12
=12X 7X-12

14.(7X-2)(-X 3)
=-7X 21X 2X-6
=-7X 23X-6

15.(5-3X)(3 2X)
=15 10X-9X-6X
=15 X-6X

16.(5-2X)(-5-X)
=-25-5X 10X 2X
=-25 5X 2X

17.(2X 3Y)(X Y)
=2X 2XY 3XY 3Y
=2X 5XY 3Y

18.(3X-Y)(X 2Y)
=3X 6XY-XY-2Y
=3X 5XY-2Y

19.(X 2Y)(2X-Y)
=2X-XY 4XY-2Y
=2x 3XY-2Y

20.(X-4Y)(2Y-3X)
=2XY-3X-8Y 12XY
=14XY-3X-8Y

21.-(3Y-5X)(Y-6X)
=(-3Y 5X)(Y-6X)
=-3Y 18XY 5XY-30X
=-3Y 23XY-30X

22.(-X-Y)(-Y-X)
=XY X Y XY
=2XY X Y



公式：
(a+b)(a+b)=2ab+a+b
(a+b)(a-b)=a-b
(a-b)(a-b)=a+b-2ab

@@@@@@@@@@@@@@

邊d係 乘邊d真係x ar??

展開?!