From 2006 through 2013, the average weekly income of an employee in a certain company is estimated by the quadratic expression 0.18n² + 6.48n + 3240 where n is the number of year after 2006. In what year did the average weekly income of an employee become 368?

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uhmmm what year is that?
Ok wait, my solution is wrong... I'll rewrite it, give me a moment
ok
Whatever I do, it never gives a exact answer... Its always an imaginary value... Is that okay?
ok ill try to explain to my teacher

Answers

2014-06-29T14:27:02+08:00
18n^2+6.48n+3240=0
18n^2+6.48n=-3240
 \frac{18n^2+6.48n}{18}=  \frac{-3240}{18}
n^2+0.36n=-180
n^2+0.36n+(0.18)^2=-180+(0.18)2
 \sqrt{(n+0.18)^2}= \sqrt{-179.9676}
n+0.18= \sqrt{-179.9676}*(-1)
n+0.18= \sqrt{1799676 }i
n=+or-  \sqrt{179.9676}i-0.18

That was confusing with all the decimals...Sorry for the late answer... :o
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