I'm solving a quadratic equation which is 2x^2-x-10=0 and I know that a=2 b=-1 and c=-10 ans with the problem put it into the formula which is -(-10 +- √ -1^2-4(2)(-10) and when I get my answer I get 79, i know there is no root number for 79. did i do something wrong?

^{2}-x-10=0

(2x-5)(x+2)=0