# How do you solve #x² - 10x = 21#?

##### 1 Answer

Jul 1, 2015

Try to factor, because if it works, it's fast. But in this case, it won't factor nicely. So move on to either completing the square or

the quadratic formula:

For

So the solutions for our quadratic equation are:

#=(10+-sqrt(100+84))/2#

#=(10+-sqrt(184))/2 = (10+-sqrt(4*46))/2#

#=(10+-2sqrt46)/2 = (2(5+-sqrt46))/2#

# = 5+-sqrt46#