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October 16th, 2014, 08:00 PM   #1
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Do I not list simplest form?

I'm getting into quadratic equations and final answers are coming in the form of $\displaystyle 0=8y^2+5y$ instead of $\displaystyle 0=8y+5$ which both come out to be the same answer. So is the author leaving out a process?
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October 16th, 2014, 08:17 PM   #2
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The latter is the simplification of the former.
$\displaystyle \textbf{Transpose } (5y) $ to the left and divide the entire equation by y. Then transpose 5 to the right again, you get the same.

Last edited by skipjack; November 22nd, 2014 at 03:02 AM.
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October 16th, 2014, 08:45 PM   #3
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0 = 8y + 5 effectively omits the solution y = 0.
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October 16th, 2014, 09:32 PM   #4
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I thank you guys for all your help, but I sometimes get the feeling you love trolling everyone.


What?



What?
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October 17th, 2014, 01:22 AM   #5
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What trolling?

$\displaystyle 8y^2 + 5y = 0$

$\displaystyle y(8y + 5) = 0$

We have the two possibilities:

$\displaystyle y = 0 \text{ or } 8y + 5 = 0$

So we have two solutions:
$\displaystyle y = 0 \text{ and }y = -\frac{5}{8}$

The equation $\displaystyle 8y + 5 = 0$ only has one solution $\displaystyle y = -\frac{5}{8}$

So what greg1313 said is perfectly accurate...The difference between the two equations is the existence of the y = 0 solution.

How is this trolling?

-Dan
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October 17th, 2014, 02:11 AM   #6
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The question is, if I was asked to put this in simplest form, which one would be correct?


Neither of your responses said this. Though I do like how it is pointed out that there is a third option of zero on one of the problems.
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October 17th, 2014, 02:22 AM   #7
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They are both in simplest form as they both have a different set of solutions. They are not the same equation.

-Dan
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