Question

Find the values of k for which the quadratic equation 3x² + kx + 3 = 0 has real and equal roots?

Answer 1

Let 3x² + kx + 3 = 0 be a quadratic equation.

It is given that, it has real and equal roots.

$$\begin{gathered} \Rightarrow \mathrm{Discriminant}=0 \\ \Rightarrow b^2-4ac=0 \\ \Rightarrow {\left(k\right)}^2-4\left(3\right)\left(3\right)=0 \\ \Rightarrow k^2=36 \\ \Rightarrow k=\pm 6 \end{gathered}$$

Hence, the values of k are –6 and 6.