SOLUTION: Please help me with this problem: The sum of the roots of the equation x squared -20x + 9 = 0 is___________ __________ The product of its roots is___________ ___________ ____

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Please help me with this problem: The sum of the roots of the equation x squared -20x + 9 = 0 is___________ __________ The product of its roots is___________ ___________ ____       Log On


   

Question 236480: Please help me with this problem:
The sum of the roots of the equation x squared -20x + 9 = 0 is______________________
The product of its roots is____________________________
Thank you very much. Carrie
Found 2 solutions by user_dude2008, JimboP1977:
Answer by user_dude2008(1862) About Me  (Show Source):
You can put this solution on YOUR website!
ax^2+bx+c

sum of roots is 20 (-b/a)
product of roots is 9 (c/a)

Answer by JimboP1977(311) About Me  (Show Source):
You can put this solution on YOUR website!
x^2-20x+9=0
I tend to use completing the square as I find this the easiest method:
(x-10)^2 - 100 = -9
so x = 91^(1/2) + 10
x = -9.539 + 10 = 0.461
OR
x = 9.539 + 10 = 19.539
SO the sum of the roots = 0.461 + 19.539 = 20
Product of the roots = 9
Does that make sense?
Do you need further clarification?