Question

If c=5 ia a root of equation kc2 - 14c -5 =
O then find the value of k.​

Answer 1

Question :

If c = 5 is a root of equation kc² - 14c -5 =  0 then find the value of k.​

Answer :

k = 3

Given :

c = 5 is a root of equation kc² - 14c -5 =  0

To find :

the value of k

Solution :

 Given quadratic equation,

  kc² - 14c - 5 = 0

Let p(c) = kc² - 14c - 5

>> c = 5 is a root of the equation.

Put c = 5,

 Since it is a root,

  when we substitute the value of c,we get 0

i.e., p(5) = 0

>> p(c) = kc² - 14c - 5

=> p(5) = 0

 

   k(5)² - 14(5) - 5 = 0

  k(25) - 70 - 5 = 0

 

  25k - 75 = 0

  25k = 75

  k = 75/25

 k = 3

∴ The value of k is 3.

Answer 2

Answer:

k = 3

Step-by-step explanation:

kc²- 14c - 5 = 0 ( c = 5 )

k(5)² - 14(5) - 5 = 0

25k - 70 - 5 = 0

25k - 75 = 0

25k = 75

k = 75/25

k = 3