a/ \(5^x+5^{x+2}=650\)
\(\Leftrightarrow5^x\left(1+5^2\right)=650\)
\(\Leftrightarrow5^x.26=650\)
\(\Leftrightarrow5^x=25\)
\(\Leftrightarrow5^x=5^2\)
\(\Leftrightarrow x=2\)
Vậy ...
b/ \(4^x+4^{x+3}=4160\)
\(\Leftrightarrow4^x\left(1+4^3\right)=4160\)
\(\Leftrightarrow4^x.65=4160\)
\(\Leftrightarrow4^x=64\)
\(\Leftrightarrow4^x=4^3\)
\(\Leftrightarrow x=3\)
Vậy ...
a) 5x + 5x+2 =650
\(\Rightarrow5^x\left(1+5^2\right)=650\)
\(\Rightarrow5^x\left(1+25\right)=650\Rightarrow5^x.26=650\Rightarrow5^x=25\Rightarrow x=2\)
b) \(4^x+4^{x+3}=4160\)
\(\Rightarrow4^x\left(1+4^3\right)=4160\Rightarrow4^x.65=4160\Rightarrow4^x=64\Rightarrow x=3\)
