MATHS題...THZ...

16. (2p+3Q)+(4p-2q)+(6p-3q)+(-6p+2q)
=2p+3q+4p-2q+6p-3q-6p+2q
=6p
17. (2t-4)-(6t-u)-(-u+2)
=2t-4-6t+u+u-2
=2u-4t-6
18. (5x +3)+(x-3)-(3x-1)
=5x+3+x-3-3x+1
=3x+4
19. (7m+n-2)+(5m+4n+2)-(3m-n-2)
=7m+n-2+5m+4n+2-3m+n+2
=9m+6n+2
20. 2a-4b-(4a-2b)+7a
=2a-4b-4a+2b+7a
=5a-2b
21. ( e-d)-(2c+3d)-(-4c-d)+(-d+c)
=e-d-2c-3d+4c+d-d+c
=e-4d+3c
22. (a-4)(a+4)
=a平方+16
23. (x-2)(x+1)
=x平方-2
24. 2(2m+n)+3(m-n)
=4m+2n+3m-3n
=7m-n
25. 4(7x+y)-2(-2x-y)
28x+4y+4x+2y
=32x+6y
26. (a+1)2次方+(a-2)2次方
=(a平方+2a+1)+(a平方-4a+4)
=a平方+2a+1+a平方-4a+4
=2a平方-2a+5

2007-08-08 16:36:39 補充：
sorry~~布幾題計錯左~~第18題------3x 1第22題------a平方-16第23題------x平方-x-2

16. Solution: 6p

17. Solution: 2u-6-4t

18. Solution: 3x+1

19. Solution: 9m+6+2

20. Solution: 5a-2b

21. Solution: e+3c-4d

22. Solution: a既2次-16

23. x既2次-x-2

24. Solution: 7m-n

25. Solution: 2(16x+3y)

26. Solution: 2a既2次+5

吾知有冇計錯~希望可以幫到你!*

2007-08-08 16:41:49 補充：
第22題錯?!*下 你計多次~冇可能...第23題~put返個root into (x-2)(x+1) 吾岩~所以...應該系條問題打錯左"