化簡
1, (x+2)(x-1) 5x+15
-------------- x ----------------
4x+8 (x+3)(x-1)
2, (x+3)3 2x+6
--------- /---------
6X+18 3X
3, 5 3
---------------- - ------------
x2+13x+36 x2+6x+8
4 5 3
----------- - -----------
x2+5x x2+3x
5 因式分解x2+4x-5,x3+5x2-x-5
化簡 x2-5x+6
--------------------
x3-3x2-4x+12
6 因式分解 2x-5x+6,x3-3x2-4x+12
化簡 1 x
------------ - --------------------
x2+5x+4 x3+3x2+3x+1
急......數學問題唔知點計
2011-09-24 2:44 am
回答 (3)
2011-09-24 7:54 am
✔ 最佳答案
1. (x+2)(x-1)/(4x+8) * (5x+15)/(x+3)(x-1)
= (x+2)(x-1)/4(x+2) * 5(x+3)/(x+3)(x-1)
= 5(x-1)/4(x-1)
= 5/4
2.
[(x+3)^3 /(6x+18)]/[(2x+6)/3x]
= (x+3)^3 /6(x+3) * 3x/2(x+3)
= 3(x+3)x/6
= x(x+3)/2
3.
5/(x^2 +13x+36) - 3/(x^2 +6x+8)
= 5/(x+4)(x+9) - 3/(x+4)(x+2)
=[5(x+2)-3(x+9)](x+2)(x+4)(x+9)
= (2x-17)/(x+2)(x+4)(x+9)
4.
5/(x^2 + 5x) - 3/(x^2 + 3x)
= 5/x(x+5) - 3/x(x+3)
= [5(x+3)-3(x+5)]/x(x+3)(x+5)
= 2x/x(x+3)(x+5)
= 2/(x+3)(x+5)
5.
x^2+4x-5 = (x+5)(x-1)
x^3+5x^2-x-5 = x^2 (x+5) - (x+5) = (x+5)(x^2 - 1) = (x+5)(x+1)(x-1)
(x^2 - 5x + 6)/(x^3 - 3x^2 - 4x + 12)
= (x-3)(x-2)/[x^2 (x-3) - 4(x-3)]
= (x-3)(x-2)/(x-3)(x-2)(x+2)
= 1/(x+2)
6.
x^2-5x+6 = (x-3)(x-2)
x^3-3x^2-4x+12 = x^2 (x-3) - 4(x-3) = (x-3)(x-2)(x+2)
1/(x^2 +5x+4) - 1/(x^3 + 3x^2 + 3x + 1)
= 1/(x+4)(x+1) - 1/(x+1)^3
= [(x+1)^2 - (x+4)]/(x+1)^3 (x+4)
= (x^2 + x - 3)/(x+1)^3 (x+4)
參考: Hope the solution can help you^^”
2011-09-28 3:09 am
1.
(x+2)(x-1)/(4x+8) * (5x+15)/(x+3)(x-1)
= (x+2)(x-1)/4(x+2) * 5(x+3)/(x+3)(x-1)
= 5(x-1)/4(x-1)
= 5/4
2.
[(x+3)^3 /(6x+18)]/[(2x+6)/3x]
= (x+3)^3 /6(x+3) * 3x/2(x+3)
= 3(x+3)x/6
= x(x+3)/2
3.
5/(x^2 +13x+36) - 3/(x^2 +6x+8)
= 5/(x+4)(x+9) - 3/(x+4)(x+2)
=[5(x+2)-3(x+9)](x+2)(x+4)(x+9)
= (2x-17)/(x+2)(x+4)(x+9)
4.
5/(x^2 + 5x) - 3/(x^2 + 3x)
= 5/x(x+5) - 3/x(x+3)
= [5(x+3)-3(x+5)]/x(x+3)(x+5)
= 2x/x(x+3)(x+5)
= 2/(x+3)(x+5)
5.
x^2+4x-5 = (x+5)(x-1)
x^3+5x^2-x-5 = x^2 (x+5) - (x+5) = (x+5)(x^2 - 1) = (x+5)(x+1)(x-1)
(x^2 - 5x + 6)/(x^3 - 3x^2 - 4x + 12)
= (x-3)(x-2)/[x^2 (x-3) - 4(x-3)]
= (x-3)(x-2)/(x-3)(x-2)(x+2)
= 1/(x+2)
6.
x^2-5x+6 = (x-3)(x-2)
x^3-3x^2-4x+12 = x^2 (x-3) - 4(x-3) = (x-3)(x-2)(x+2)
1/(x^2 +5x+4) - 1/(x^3 + 3x^2 + 3x + 1)
= 1/(x+4)(x+1) - 1/(x+1)^3
= [(x+1)^2 - (x+4)]/(x+1)^3 (x+4)
= (x^2 + x - 3)/(x+1)^3 (x+4)
(x+2)(x-1)/(4x+8) * (5x+15)/(x+3)(x-1)
= (x+2)(x-1)/4(x+2) * 5(x+3)/(x+3)(x-1)
= 5(x-1)/4(x-1)
= 5/4
2.
[(x+3)^3 /(6x+18)]/[(2x+6)/3x]
= (x+3)^3 /6(x+3) * 3x/2(x+3)
= 3(x+3)x/6
= x(x+3)/2
3.
5/(x^2 +13x+36) - 3/(x^2 +6x+8)
= 5/(x+4)(x+9) - 3/(x+4)(x+2)
=[5(x+2)-3(x+9)](x+2)(x+4)(x+9)
= (2x-17)/(x+2)(x+4)(x+9)
4.
5/(x^2 + 5x) - 3/(x^2 + 3x)
= 5/x(x+5) - 3/x(x+3)
= [5(x+3)-3(x+5)]/x(x+3)(x+5)
= 2x/x(x+3)(x+5)
= 2/(x+3)(x+5)
5.
x^2+4x-5 = (x+5)(x-1)
x^3+5x^2-x-5 = x^2 (x+5) - (x+5) = (x+5)(x^2 - 1) = (x+5)(x+1)(x-1)
(x^2 - 5x + 6)/(x^3 - 3x^2 - 4x + 12)
= (x-3)(x-2)/[x^2 (x-3) - 4(x-3)]
= (x-3)(x-2)/(x-3)(x-2)(x+2)
= 1/(x+2)
6.
x^2-5x+6 = (x-3)(x-2)
x^3-3x^2-4x+12 = x^2 (x-3) - 4(x-3) = (x-3)(x-2)(x+2)
1/(x^2 +5x+4) - 1/(x^3 + 3x^2 + 3x + 1)
= 1/(x+4)(x+1) - 1/(x+1)^3
= [(x+1)^2 - (x+4)]/(x+1)^3 (x+4)
= (x^2 + x - 3)/(x+1)^3 (x+4)
參考: me
2011-09-24 8:34 pm
1.
(x+2)(x-1)/(4x+8) * (5x+15)/(x+3)(x-1)
= (x+2)(x-1)/4(x+2) * 5(x+3)/(x+3)(x-1)
= 5(x-1)/4(x-1)
= 5/4
2.
[(x+3)^3 /(6x+18)]/[(2x+6)/3x]
= (x+3)^3 /6(x+3) * 3x/2(x+3)
= 3(x+3)x/6
= x(x+3)/2
3.
5/(x^2 +13x+36) - 3/(x^2 +6x+8)
= 5/(x+4)(x+9) - 3/(x+4)(x+2)
=[5(x+2)-3(x+9)](x+2)(x+4)(x+9)
= (2x-17)/(x+2)(x+4)(x+9)
4.
5/(x^2 + 5x) - 3/(x^2 + 3x)
= 5/x(x+5) - 3/x(x+3)
= [5(x+3)-3(x+5)]/x(x+3)(x+5)
= 2x/x(x+3)(x+5)
= 2/(x+3)(x+5)
5.
x^2+4x-5 = (x+5)(x-1)
x^3+5x^2-x-5 = x^2 (x+5) - (x+5) = (x+5)(x^2 - 1) = (x+5)(x+1)(x-1)
(x^2 - 5x + 6)/(x^3 - 3x^2 - 4x + 12)
= (x-3)(x-2)/[x^2 (x-3) - 4(x-3)]
= (x-3)(x-2)/(x-3)(x-2)(x+2)
= 1/(x+2)
6.
x^2-5x+6 = (x-3)(x-2)
x^3-3x^2-4x+12 = x^2 (x-3) - 4(x-3) = (x-3)(x-2)(x+2)
1/(x^2 +5x+4) - 1/(x^3 + 3x^2 + 3x + 1)
= 1/(x+4)(x+1) - 1/(x+1)^3
= [(x+1)^2 - (x+4)]/(x+1)^3 (x+4)
= (x^2 + x - 3)/(x+1)^3 (x+4)
(x+2)(x-1)/(4x+8) * (5x+15)/(x+3)(x-1)
= (x+2)(x-1)/4(x+2) * 5(x+3)/(x+3)(x-1)
= 5(x-1)/4(x-1)
= 5/4
2.
[(x+3)^3 /(6x+18)]/[(2x+6)/3x]
= (x+3)^3 /6(x+3) * 3x/2(x+3)
= 3(x+3)x/6
= x(x+3)/2
3.
5/(x^2 +13x+36) - 3/(x^2 +6x+8)
= 5/(x+4)(x+9) - 3/(x+4)(x+2)
=[5(x+2)-3(x+9)](x+2)(x+4)(x+9)
= (2x-17)/(x+2)(x+4)(x+9)
4.
5/(x^2 + 5x) - 3/(x^2 + 3x)
= 5/x(x+5) - 3/x(x+3)
= [5(x+3)-3(x+5)]/x(x+3)(x+5)
= 2x/x(x+3)(x+5)
= 2/(x+3)(x+5)
5.
x^2+4x-5 = (x+5)(x-1)
x^3+5x^2-x-5 = x^2 (x+5) - (x+5) = (x+5)(x^2 - 1) = (x+5)(x+1)(x-1)
(x^2 - 5x + 6)/(x^3 - 3x^2 - 4x + 12)
= (x-3)(x-2)/[x^2 (x-3) - 4(x-3)]
= (x-3)(x-2)/(x-3)(x-2)(x+2)
= 1/(x+2)
6.
x^2-5x+6 = (x-3)(x-2)
x^3-3x^2-4x+12 = x^2 (x-3) - 4(x-3) = (x-3)(x-2)(x+2)
1/(x^2 +5x+4) - 1/(x^3 + 3x^2 + 3x + 1)
= 1/(x+4)(x+1) - 1/(x+1)^3
= [(x+1)^2 - (x+4)]/(x+1)^3 (x+4)
= (x^2 + x - 3)/(x+1)^3 (x+4)
參考: Tracy
收錄日期: 2021-04-13 18:15:58
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