Question

1. The value of k for which equation 9x2 + 8xk+8 = 0 has equal roots is:

Answer 1

Answer:

Option C

+ or - 3

Step-by-step explanation:

A quadratic equation will have equal roots if its Discriminant is equal to zero.

the discriminant in this case is $b^{2}- 4 ac$

considering the equation,

$9x^{2} + 8xk+8 = 0$

a = 9, b= 8k, c=8

Replacing the variables in the original equation with their respective values, we will have:

$8k^{2}- 4 \times 9 \times 8=0\\64k^{2}=288\\k=\sqrt{288/64} =\sqrt{9/2}$

Note: The values of k are meant to be + or -2.12 as seen from the workings

However, these are not in the options given. the closest choice to it

is + or - 3