Question 248228
p^2 + 3p - 9 = 0
what is the quadratic formula?
the quadratic equation is ax^2+bx+c=0
in your equation a=1; b=3 and c=-9
we solve for x to get the quadratic formula
It is wise to calculate the discriminant (b^2-4ac) first. You have to do it anyways.
It will tell you about the solutions.
It says that your equation can be factored but that is not normal factoring

*[invoke quadratic "x", 1,3, -9 ]

 What other way can we solve this equation?
complete the square
p^2 + 3p - 9 = 0
p^2+3p=9=36/4
add (3/2)^2 to both sides
p^2+3p+9/4=(36+9)/4
p^2+3p+9/4=(45)/4
factor 
(p+3/2)^2=(3sqrt(5)/2)^2
p+3/2=+\-(3sqrt)5//2
subtract 3/2 from both sides
p=-3/2+3sqrt(5)/2
p=-3/2-3sqrt(5)/2
factor out 3/2