a) \(3^{x+1}=81\)
\(\Rightarrow3^{x+1}=3^4\)
\(\Rightarrow x+1=4\)
\(\Rightarrow x=3\)
Vậy \(x=3\)
b) \(3^x+2^{x+1}=324\)
\(\Rightarrow3^x+3^x.3=324\)
\(\Rightarrow3^x.\left(1+3\right)=324\)
\(\Rightarrow3^x.4=324\)
\(\Rightarrow3^x=81\)
\(\Rightarrow3^x=3^4\)
\(\Rightarrow x=4\)
Vậy \(x=4\)
a, Ta có \(3^{x+1}=81\Rightarrow3^{x+1}=3^4\)
\(\Rightarrow x+1=4\Rightarrow x=3\)
Vậy x= 3
b, Ta có \(3^x+3^{x+1}=324\Rightarrow3^x+3^x.3=324\)
\(\Rightarrow3^x.\left(1+3\right)=324\Rightarrow3^x.4=324\)
\(\Rightarrow3^x=81\Rightarrow3^x=3^4\Rightarrow x=4\)
Vậy x=4
3\(^{x+1}\)=81
\(\Rightarrow\)3\(^{x+1}\)=3\(^4\)
\(\Rightarrow\) x+1=4
\(\Rightarrow\) x=4-1
\(\Rightarrow\)x=3
