If the roots of the quadratic equation 2kx^2 + (2a + b)x - ab = 0 are (-2, a), the value of k is:
i) -1
ii) -2
iii) 1
iv) 2
Please show the working also

Question

If the roots of the quadratic equation 2kx^2 + (2a + b)x - ab = 0
are (-2, a), the value of k is:
i) -1
ii) -2
iii) 1
iv) 2
Please show the working also

Answer

Given: The quadratic equation

is given and the roots of the equation are

To find: The value of

Solution: The roots of the quadratic equation are stated as

Roots of a quadratic equation mean when the values are put in the equation they satisfy it that is the resultant value is 0 Therefore, putting the value of

we get,

⇒

As

hence,

If the roots of the quadratic equation 2kx^2 + (2a + b)x - ab = 0 are (-2, a), the value of k is: i) -1 ii) -2 iii) 1 iv) 2 Please show the working also

If the roots of the quadratic equation 2kx^2 + (2a + b)x - ab = 0 are (-2, a), the value of k is:
i) -1
ii) -2
iii) 1
iv) 2
Please show the working also