Posted by Untamed on Monday, December 5, 2011 at 7:42pm.
Solve the following quadratic equation(as exact values) using the quadratic formula.
x^210x15=0
I got 5+2sqrt10/2.
^ Sorry hard to write it out. But basically there is a 5 there, the negative sign is supposed to be under the positive sign, then there is a two outside of the radicand, and inside the radicand is 10, all under 2.

Math  MathMate, Monday, December 5, 2011 at 8:06pm
The answer is correct if it was meant to be, after cancelling the two's:
5±√(10)

Math  correction  MathMate, Monday, December 5, 2011 at 8:10pm
The answer is correct if it was meant to be (without the 2 in the denominator):
5±2√(10)

Math  Untamed, Monday, December 5, 2011 at 8:15pm
Where does that two in the denominator go? Since it has to cancel out with all terms.

Math  MathMate, Monday, December 5, 2011 at 8:52pm
x=(b±sqrt(b²4ac))/2a
a=1
b=10
c=15
so substituting,
x=(10±sqrt((10)²4(1)(15)))/2
=(10±sqrt(160))/2
=(10±4sqrt(10))/2
=5±2sqrt(10)
You may have (like I did) subtracted 4ac (and got 40) instead of adding to get 160.
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