SOLUTION: A common student error when solving a quadratic equation is simplifying incorrectly. Consider the following INCORRECT solution: 2+/- the square root of 7 divided by 2 = 1+/

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Question 370623: A common student error when solving a quadratic equation is simplifying incorrectly. Consider the following INCORRECT solution:
2+/- the square root of 7 divided by 2
=
1+/- square root of 7
Explain why x= 1+-sqrt7 is the incorrect solution.
Is this not able to be factored any further from 2+-sqrt7/2 because the whole numerator needs divided by 2?

Found 3 solutions by amoresroy, jim_thompson5910, mananth:
Answer by amoresroy(361) About Me  (Show Source):
You can put this solution on YOUR website!
A common student error when solving a quadratic equation is simplifying incorrectly. Consider the following INCORRECT solution:
2+/- the square root of 7 divided by 2
=
1+/- square root of 7
Explain why x= 1+-sqrt7 is the incorrect solution.
The correct solution is
x= 1+-(sqrt7)/2
You need to divide the numerator by 2

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Yes, the ENTIRE numerator is divided by 2 which means that you'll need to reduce sqrt%287%29%2F2, but since you can't, it's best to leave the solution as %282%2B-sqrt%287%29%29%2F2

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
x=%28+2%2Bsqrt%287%29%29%2F2
..
you have youself answered the question.As you see above %282%2Bsqrt%287%29%29
is in the numerator
when you simplify each term in the numerator has to be divided by 2
x=%28%282%2F2%29%2B%28sqrt%287%29%29%2F2%29%29
=x=%281%2B%28sqrt%287%29%29%2F2%29
if you need to simplify further you have to use a calculator to write the answer in decimals.
x= 1+3.228
x= 4.228
..
the same applies for the other root.
...
m.ananth@hotmail.ca