form 4 maths (ratio)

Question

If 6x²-5xy-4y²=0

find

x²+y²/2xy+3y²


Show steps pls.

Answer 1

Simple question,
6x²-5xy-4y²=0
By factorization:
(3x-4y)(2x+y)=0
x=4/3y or x=-1/2y
x²+y²/2xy+3y²

代入x=4/3y
(16/9y²+y²) / (8/3y²+3y²)
=(25/9y²) / (17/3y²)
=25/51
代入x=-1/2y
[(-1/2y)²+y²] / (2*-1/2y*y+3y²)
=5/4y² / 2y²
=5 / 8
Two answers either 25/51 or 5/8

2007-03-26 19:24:38 補充：
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2007-03-28 18:12:39 補充：
我其實想刪除，讓一讓樓上那位，佢答得快，應有鼓勵！