The solution to your problem is 8 (:
Do you have a picture of the whole question?
The answer for this question is to treat people the way you want to be treated if you want the answer click the link below
First set everything to 0.

Giving you A= 1 , B= 1 and C= -5
Then input everything into the quadratic formula and either solve by hand or use a calculator.
Note exact values are found by hand, decimals are found using a calculator.
I've attached the graphs to this answer. I hope they help.