\(5^{x+1}+5^x=30\)
\(\Rightarrow5^x\cdot\left(5+1\right)=30\)
\(\Rightarrow5^x\cdot6=30\)
\(\Rightarrow5^x=30:6\)
\(\Rightarrow5^x=5^1\)
\(\Rightarrow x=1\)
Vậy x=1
\(5^{x+1}+5^x\text{=}30\)
\(5^x.5+5^x=30\)
\(5^x.\left(5+1\right)\text{=}30\)
\(5^x\text{=}5\text{=}5^1\)
\(x\text{=}1\)