Question

If $\frac{10}{3}\times 3^x-3^{x-1}=81$, then the value of $x$ is ___________.

• A. $2$
• B. $1$
• C. $3$
• D. $0$

Answer 1

The correct option is C $3$

$\frac{10}{3}\times 3^x=10\times 3^{x-1}$

To find, $\frac{10}{3}\times 3^x-3^{x-1}=81$

$\Rightarrow \left(3^{x-1}\right)\times 9=81$

$3^{x-1}=3^2$

$x-1=2$

$\therefore x=3$