Solve x^2 + 7x +9 = 0 using the quadratic formula

We know that the quadratic formula for finding the roots
of the quadratic equation is:

x1 = [-b + sqrt(b^2 -
4ac)]/2a

x2 = [-b - sqrt(b^2 -
4ac)]/2a

We know that the expression under the square root 
is called the discriminant of the quadratic, delta.

If
delta is positive, the equation has 2 real distinc
roots.

If delta is zero, the equation has 2 equal real
roots.

We'll compute delta. For this reason, we'll identify
a,b,c:

a = 1 , b = 7 , c =
9

delta = 49 - 36

delta = 13
> 0

Since delta is positive, the equtaion has 2 real
distinct roots:

x1 = (-7+sqrt
13)/2

x2 = (-7-sqrt
13)/2