#2 (a) Find the values of the constants A & B such that x*-8x+12=(x-A)*+B
(b) Hence factorize the expression x*-8x+12
(c) By using the result in (b), simplify 2 + 1
--------------- --------
x*-8x+12 x-6
* = 2次方
Maths question!! Please help!!
2008-01-07 6:56 am
回答 (3)
2008-01-07 7:22 am
✔ 最佳答案
(a)x^2-8x+12
= (x^2-8x+16) - 4
=(x-4)^2 - 4
(b)
x^2 -8x+12
= (x-4)^2 - 4 (by result of (a))
= [(x-4) - 2] [(x-4) +2]
= (x-6) (x-2)
(c)
[2/(x -8x+12)] + 1/(x-6)
= [2/(x-6)(x-2)] + 1/(x-6)
= [2/(x-2) + 1]/(x-6)
= {[2 + x-2]/(x-2)} /(x-6)
= x/[(x-2)(x-6)]
=x /[x^2 - 8x +12]
2008-01-07 7:33 pm
(a) x*-8x+12=(x-A)*+B
L.H.S. = x*-8x+12
R.H.S.= (x-A)*+B
=x* - 2Ax + A* + B
-8x = -2Ax
A = 4
A* + B =12
4* + B = 12
B = -4
(b) x*-8x+12
=(x-A)*+B
=(x-4)* - 4
L.H.S. = x*-8x+12
R.H.S.= (x-A)*+B
=x* - 2Ax + A* + B
-8x = -2Ax
A = 4
A* + B =12
4* + B = 12
B = -4
(b) x*-8x+12
=(x-A)*+B
=(x-4)* - 4
2008-01-07 8:40 am
a) x*-8x+12=(x-A)*+B
x*-8x+12=x*-2Ax+A*+B
=x* - 2Ax + (A* + B)
So, 2A = 8
A = 4
(A*+B) = 12
16 + B = 12
B = -4
x*-8x+12=x*-2Ax+A*+B
=x* - 2Ax + (A* + B)
So, 2A = 8
A = 4
(A*+B) = 12
16 + B = 12
B = -4
參考: me
收錄日期: 2021-04-13 14:53:53
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