Question 821667: Find two consecutive negative odd integers whose product is 399
Answer by TimothyLamb(4379)   (Show Source):
You can put this solution on YOUR website! ---
x - y = -2
x = y - 2
xy = 399
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xy = 399
(y - 2)y = 399
yy - 2y - 399 = 0
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the above quadratic equation is in standard form, with a=1, b=-2, and c=-399
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to solve the quadratic equation, by using the quadratic formula, copy and paste this:
1 -2 -399
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the two real roots (i.e. the two x-intercepts), of the quadratic are:
y = 21
y = -19
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positive root doesn't satisfy the problem statement, so use the negative root:
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answer:
y = -19
x = -21
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