Math
posted by Untamed on .
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.

The answer is correct if it was meant to be, after cancelling the two's:
5±√(10) 
The answer is correct if it was meant to be (without the 2 in the denominator):
5±2√(10) 
Where does that two in the denominator go? Since it has to cancel out with all terms.

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.