SOLUTION: find the missing root if 8 is a root of x^2+16x+c=0 I tried the sum formula which is -b/ a so i took -16/1 and got - 16 for my answer which was not right

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: find the missing root if 8 is a root of x^2+16x+c=0 I tried the sum formula which is -b/ a so i took -16/1 and got - 16 for my answer which was not right       Log On


   

Question 702893: find the missing root if 8 is a root of x^2+16x+c=0
I tried the sum formula which is -b/ a so i took -16/1 and got - 16 for my answer which was not right
Answer by mouk(232) About Me  (Show Source):
You can put this solution on YOUR website!
you are nearly correct:

Using the formula for the sum of roots:
+alpha+%2B+beta+=+-b%2Fa+
gives:

+8+%2B+beta+=+-16%2F1+
+beta+=+-16+-+8+
+beta+=+-24+