Bài giải
\(3\left(5^x-1\right)-2=70\)
\(3\left(5^x-1\right)=72\)
\(5^x-1=24\)
\(5^x=25=5^2\)
\(x=2\)
Bài làm :
Ta có :
\(3\left(5^x-1\right)-2=70\)
\(\Leftrightarrow3\left(5^x-1\right)=72\)
\(\Leftrightarrow5^x-1=24\)
\(\Leftrightarrow5^x=25\)
\(\Leftrightarrow x=2\)
Vậy x=2
Bài làm :
\(3.\left(5^x-1\right)-2=70\)
\(\Rightarrow3.\left(5^x-1\right)=70+2\)
\(\Rightarrow3.\left(5^x-1\right)=72\)
\(\Rightarrow5^x-1=72:3\)
\(\Rightarrow5^x-1=24\)
\(\Rightarrow5^x=25\)
\(\Rightarrow5^x=5^2\)
\(\Rightarrow x=2\)
Vậy x = 2 .
Học tốt
