My Math Forum quadratic formula...But this time I should be getting Decimal

 Algebra Pre-Algebra and Basic Algebra Math Forum

April 25th, 2017, 07:46 AM   #11
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Quote:
 Originally Posted by GIjoefan1976 Hmm okay, I guess because the line that makes me think division...plus if we are to add and - the 1 then wouldn't 29 plus equal 30 and minus 1 equal 28?
WHOA.

First, the line that makes you think division means division, pure and simple. I suspect what you are saying is that in arithmetic classes you are expected to get a numeric approximation if a division does not have a neat answer. That is not true in algebra. If you can't get an exact decimal answer in algebra, you should leave the answer in fractional but exact form unless told otherwise.

Second, there is no plus or minus sign in front of 1. If you were correct that

$\sqrt{29}= 29$ the correct solutions would be

$x= \dfrac{1 \pm 29}{2} = \dfrac{30}{2} \text { or } \dfrac{-\ 28}{2} = 15 \text { or } -\ 14.$

Finally, it is of course wrong that 29 is the square root of 29. Multiply 29 times it self. You will not get 29. Only two real numbers equal their own square root, namely zero and one.

April 26th, 2017, 09:07 AM   #12
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Quote:
 Originally Posted by GIjoefan1976 Hmm okay, I guess because the line that makes me think division...plus if we are to add and - the 1 then wouldn't 29 plus equal 30 and minus 1 equal 28?
If that were just 29, then 1+ 29= 30 but 1- 29= -28, not 28.

However it is $\sqrt{29}$ which is approximately 5.3851648. 1+ that is 6.3851648 and half of that 3.1925824. 1- that is -4.3851648 and half of that is -2.1925824.

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