mary and tony try to solve a quadratic equation 2x^2+bx+c = 0, where b and c are integers. mary copies the value of b wrongly. the roots that she gets are 5 and 1/2. tony copies the value of c wrongly. the roots that he gets are 4 and -1/2.
find the original equation.
f.4 mathz
2009-10-01 3:25 am
回答 (1)
2009-10-01 3:35 am
✔ 最佳答案
Mary's equation is 2(x - 5)(x - 1/2) = 0(x - 5)(2x - 1) = 0
2x^2 - 11x + 5 = 0 => c = 5
Tony's equation is 2(x - 4)(x + 1/2) = 0
(x - 4)(2x + 1) = 0
2x^2 - 7x - 4 = 0 => -7
The original equation is 2x^2 - 7x + 5 = 0
2009-09-30 19:37:30 補充：
Correction: 2x^2 - 7x - 4 = 0 => b = -7
收錄日期: 2021-04-23 23:20:51
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https://hk.answers.yahoo.com/question/index?qid=20090930000051KK01237