Formulae

2008-12-19 3:08 am
p. 214
42.
-x + 2y 3x + 6y
____________ + _____________
4y + 2x 2x - 4y

43.
3x 6y
______ ^ ________
x -2 2x - 4y

51.
p +t
a = ------------
s - t

52.
ab + c (b +1) =a

回答 (5)

2008-12-23 7:19 pm
✔ 最佳答案
(-x+2y)/(4y+2x)+(3x+6y)/(2x-4y)
=[(-x+2y)(x-2y)+(3x+6y)(x+2y)]/(2x^2-8y^2)
=(-x^2+8xy-4y^2+3x^2+6xy+12y^2)/(2x^2-8y^2)
=(2x^2+14xt+8y^2)/(2x^2-8y^2)
=(x^2+7xy+4y^2)/(x^2-4y^2)//

3x/(x-2)+6y/(2x-4y)
=[(3x)(2x-4y)+6y(x-2)]/[(2x-4y)(x-2)]
=(6x^2-6xy-12)/[(2x-4y)(x-2)]
=(3x^2-3xy-4)/[(x-2y)(x-2)]//

x=(p-t)/(s-t)
sx-tx=p-t
sx-p=tx-t
t=(sx-p)/(x-1)//



2008-12-20 9:55 pm
sorry,我只是跟book打,我也不知以上的是什麼.
2008-12-20 2:56 am
題目很不清楚!!!
2008-12-19 8:51 am
打清楚題目
2008-12-19 6:00 am
完全不明你想問什麼? Change subject? Factorization?

^ 是什麼?


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