Question

 5^x + 5^x+1 + 5^x+2 = 3875.

Answer 1

\(\Rightarrow5^x\left(1+5+5^2\right)=3875\\ \Rightarrow5^x=\dfrac{3875}{31}=125=5^3\\ \Rightarrow x=3\)

Answer 2

\(\Leftrightarrow5^x+5^x.5+5^x.25=3875\\ \Leftrightarrow5^x\left(1+5+25\right)=5^3.31\\ \Leftrightarrow5^x.31=5^3.31\\ \Leftrightarrow5^x=5^3\\ \Leftrightarrow x=3\)