問中二的數+10%

1. (x+y)*2 - (x-y)*2
= x*2 + 2xy + y*2 - x*2 + 2xy - y*2
= 4xy

2. (3x-1)*2 + (4x-1)*2 + (14x-3)
= 9x*2 - 6x + 2 + 16x*2 - 8x + 2 + 14x - 3
= 25x*2 + 1

3. x*2 + 6x - 1 ≡ (x + p)*2 + q
x*2 + 6x - 1 ≡ x*2 + 2px +(p*2 + q)
then, 2p = 6 , (p*2 + q) = -1
p = 3 , 3*2 + q = -1
q = -10

4. 3x - 4y +5x - 2y + 1
= 8x - 6y + 1

5. 2x*2 - 4x*2 + 3x - 5x + 9 + 7
= -2x*2 - 2x + 16
= -x*2 - x + 8

6. ( -2x*3 + 6x - 3 ) + ( 7x*3 - 6x + 2 )
= -3x*3 + 6x - 3 + 7x*3 - 6x + 2
= 4x*3 - 1


希望可以幫到您

2007-07-17 14:51:32 補充：
第6題錯了正確答案如下 : 6. ( -2x*3 6x - 3 ) ( 7x*3 - 6x 2 )= -2x*3 6x - 3 7x*3 - 6x 2= 5x*3 - 1抱歉