Question

if the sum of the zeroes of the quadratic polynomial 3x²-kx+6 is 3 then find the value of k

Answer 1

$$\begin{gathered} \mathrm{Let}\mathrm{p}\left(\mathrm{x}\right)=3{\mathrm{x}}^2-\mathrm{kx}+6 \\ \mathrm{Now},\mathrm{sum}\mathrm{of}\mathrm{zeroes}=-\frac{\mathrm{coefficient}\mathrm{of}\mathrm{x}}{\mathrm{coefficient}\mathrm{of}{\mathrm{x}}^2} \\ \Rightarrow 3=-\frac{\left(-\mathrm{k}\right)}{3} \\ \Rightarrow \boxed{\mathbf{k}\mathbf{}\mathbf{=}\mathbf{}\mathbf{9}} \end{gathered}$$