Suppose the two roots are r and 3r.
Then we have
3(x-r)(x-3r) = 0,
and thus
3x² - 12rx + 9r² = 0 ...... (*)
Compare (*) to the original equation,
we obtain
12r = 4 and 9r² = p.
Hence
r = 4/12 = 1/3 and p = 9(1/3)² = 1.
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由 benice 於 星期二 十一月 06, 2012 1:57 am
由 kenlkp 於 星期日 十一月 04, 2012 12:00 pm
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[高中]F4 maths help me
由 kenlkp 於 星期日 十一月 04, 2012 11:58 am
if one root of 3x^2-4x+p=0 is three times the other root,find the value of p