Question

• A. 9
• B. 8
• C. 6
• D. 7

Answer 1

Answer:

B. 8

$3^{x-2}+3^x=7290$

$\frac{3^x}{3^2}+3^x=7290$

$3^x(\frac19+1)=7290$

$3^x(\frac{10}{9})=7290$

$3^x=\frac{7290\times 9}{10}$

$3^x=729 \times 9$

$3^x=3^6\times 3^2$

$3^x=3^8$

$x=8$