\(3^{x+2}-3^x=24\)
\(\Rightarrow3^x.3^2-3^x=24\)
\(\Rightarrow3^x\left(3^2-1\right)=24\)
\(\Rightarrow3^x.8=24\)
\(\Rightarrow3^x=3\)
\(\Rightarrow3^x=3^1\)
\(\Rightarrow x=1\)
Vậy x = 1
\(3^{x+2}-3^x=24\Leftrightarrow3^x\left(3^2-1\right)=24\)
\(\Leftrightarrow3^x.8=24\Leftrightarrow3^x=3\Leftrightarrow x=1\)
3x+2−3x=24
⇒3x.32−3x=24
⇒3x(32−1)=24
⇒3x.8=24
⇒3x=3
⇒3x=31
⇒x=1
Vậy x = 1