Question

Tìm x biết' \(5^x+5^{x+2}=650\)

Answer 1

\(5^x+5^{x+2}=650\Rightarrow5^x+5^x\cdot5^2=650\\ 5^x\left(25+1\right)=650\).

.\(5^x\cdot26=650\\ 5^x=\dfrac{650}{26}=25=5^2\\ \Rightarrow x=2\)

Answer 2

\(5^x+5^{x+2}=650\Rightarrow5^x+5^x.5^2=650\)\(5^x.\left(5^2+1\right)=650\Rightarrow5^x.26=650\)

\(\Rightarrow5^X=25\Rightarrow5^x=5^2\Rightarrow x=2\)

vậy x=2