SOLUTION: 11 It is given that -1/2 is a root of the equation 10x^2-9x+k=0, where k is a constant. Find (a) the value of k (b) the other root

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: 11 It is given that -1/2 is a root of the equation 10x^2-9x+k=0, where k is a constant. Find (a) the value of k (b) the other root      Log On


   

Question 313587: 11 It is given that -1/2 is a root of the equation 10x^2-9x+k=0, where k is a constant. Find
(a) the value of k
(b) the other root
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
It is given that -1/2 is a root of the equation 10x^2 - 9x + k = 0, where k is a constant.
A root of -1/2 give us a factor of: (2x + 1)
:
The other factor to satisfy the middle term of -9x: (5x - 7)
:
FOIL (2x + 1)(5x - 7)
10x^2 - 14x + 5x - 7
10x^2 - 9x - 7 = 0
Find
(a) the value of k
k = -7
:
(b) the other root
5x - 7 = 0
5x = 7
x = 7%2F5