Question

Find sum of roots of the equation 4^x-7.2^x+6=0 .

Answer 1

$$\begin{gathered} 4^{\mathrm{x}}-7.2^{\mathrm{x}}+6=0 \\ \Rightarrow {\left(2^{\mathrm{x}}\right)}^2-7.2^{\mathrm{x}}+6=0 \\ \Rightarrow {\mathrm{y}}^2-7\mathrm{y}+6=0\left[\mathrm{put}{2}^{\mathrm{x}}=\mathrm{y}\right] \\ \mathrm{Sum}\mathrm{of}\mathrm{the}\mathrm{roots}=-\frac{\mathrm{coefficient}\mathrm{of}\mathrm{y}}{\mathrm{coefficient}\mathrm{of}{\mathrm{y}}^2}=7 \end{gathered}$$