Question

Tìm x:

\(3^x.3^{x+2}=7290\)

(các bn ghi rõ cách giải giúp mình nha, thank you )

Answer 1

\(3^x+3^{x+2}=7290\)

\(3^x+3^x.3^2=7290\)

\(3^x.\left(1+9\right)=7290\)

\(3^x.10=7290\)

\(\Rightarrow3^x=729\)

\(\Rightarrow x=6\)

 

Answer 2

\(3^x+3^{x+2}=7290\Rightarrow3^x.\left(1+3^2\right)=7290\Rightarrow3^x=729=3^6\Rightarrow x=6\)

Answer 3

\(3^x\cdot3^{x+2}=7290\)

\(\Leftrightarrow3^x=729\)

hay x=6