Question

If one root of the equation 3x2

–kx -2 = 0 is 2, find the value of k. Also find the other root.

Answer 1

Answer:

As 2 is the root, it must satisfy the equation.

substitute x=2 in the given equation,

we get 3(2)^2-k(2)-2=0

12–2k-2=0

2k=10

so, k=5

Now substitute k value in the equation, we get 3x^2–5x-2=0

By factorization we can write it as 3x^2–6x+x-2=0

3x(x-2)+(x-2)=0

(x-2)(3x+1)=0

x-2=0, 3x+1=0

x=2, x=-1/3

so other root is -1/3