中一數學難題....help!! (10分)

2006-11-29 1:35 am
請簡化下列各題目..
1. (m+3)*+(m-3)*

2. (y+3)*+3(y-1)+2

3. 16t* - (4t-3)(4t+3)

4. (a-2b)(a*+ab+b*)

5. (m+1)(m+2)(m+3)

備註: * = 二次方

回答 (6)

(1) (m*+6m+9)+(m*-6m+9)
=2m*+18
=m*+9

(2) (y*+6y+9)+3y-3+2
=y*+9y+8

(3) 16t*-(16t*-9)
=9

(4) a^ -2a*b+a*b -2ab* +ab* -2b^
=a^ - a*b - ab* -2b^

(5) (m*+4m+2)(m+3)
=m^+4m*+3m*+2m+12m+2+6
=m^+7m*+14m+8


^ = 三次方 ; * = 二次方






唔知啱唔啱
2006-11-29 1:59 am
1.(m+3)*+(m-3)*
=(m*+6m+9)+(m*-6m+9)
=m*+6m+9+m*-6m+9
=2m*+18

2.(y+3)*+3(y-1)+2
=(y*+6y+9)+3y-3+2
=y*+6y+9+3y-3+2
=y*+9y+8

3.16t* - (4t-3)(4t+3)
=16t*-(16t*-9)
=16t*-16t*+9
=9

4.(a-2b)(a*+ab+b*)
=(a-2b)(a+b)*
=(a*-2b*)*
=a^4a*b*+4b^

5.(m+1)(m+2)(m+3)
=[m(m+1)+2(m+1)](m+3)
=(m*+m+2m+2)(m+3)
=(m*+3m+2)(m+3)
=m(m*+3m+2)+3(m*+3m+2)
=m~+3m*+2m+3m*+9m+6
=m~+6m*+11m+6

備註: * = 二次方
~ = 3次方
^ = 4次方
參考: me
2006-11-29 1:57 am
1) m*+6m+9+m*-6m+9
=2m*+18

=2(m*+9)
2) y*+6y+9+3y-3+2
=y*+9y+8

=(y+8)(y+1)
3) 16t*-(16t*-9)
=9
4) a^3+a*b+ab*-2a*b-2ab*-2b^3
5) (m*+3m+2)(m+3)
=m^3+3m*+2m+3m*+9m+6
=m^3+6m*+11m+6

註:
* = 二次方
^3 = 三次方
或者可能有大小階的分別。
2006-11-29 1:51 am
1. (m+3)(m+3) + (m-3)(m-3)
= (m*+6m+9) + (m*-6m+9)
= 2m*+18

2. (y+3)*+3(y-1)+2
= (y*+6y+9)+(3y-3)+2
= y*+9y+8
= (y+1)(y+8)

3. 16t* - (4t-3)(4t+3)
= 16t* - (16t*-9)
= 16t* - 16t* + 9
= 9

4. (a-2b)(a*+ab+b*)
= a**+a*b+ab*-2a*b-2ab*-2b**
= a**-a*b-ab*-2b**

5. (m+1)(m+2)(m+3)
= (m*+2m+1m+2)(m+3)
= (m*+3m+2)(m+3)
= (m**+3m*+3m*+9m+2m+6)
= m**+6m*+11m+6

備註: * = 二次方 ; ** = 三次方
2006-11-29 1:50 am
1)m2次+6m+9+m2次-6m+9=2m2次+18

2)y2次+6y+9+3y-3+2=y2次+9y+8

3)16t2次-16t2次-12t+12t+9=9

4)a3次+a2次b+ab2次-2a2次b-2ab2次-2b3次=a3次-a2次b-ab2次-2b3次

5)(m2次+2m+m+2)(m+3)=m3次+3m2次+3m2次+9m+2m+6=m3次+6m2次+11m+6
2006-11-29 1:42 am
1.(m*+6m*+9)+(m*-6m*+9)=2M*+18=2(m*+9)


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