\(3^{x-1}+3^x+3^{x+1}=39< =>3^x:3+3^x+3^x.3=39< =>3^x.\dfrac{1}{3}+3^x.1+3^x.3=39< =>3^x.\left(\dfrac{1}{3}+1+3\right)=39< =>3^x.\dfrac{13}{3}=39< =>3^x=39:\dfrac{13}{3}< =>3^x=9< =>3^x=3^2< =>x=2\)
\(3^{x-1}+3^x+3^{x+1}=39\)
\(\Rightarrow\dfrac{1}{3}.3^x+3^x+3.3^x=39\)
\(\Rightarrow3^x.\left(\dfrac{1}{3}+1+3\right)=39\)
\(\Rightarrow\dfrac{13}{3}.3^x=39\)
\(\Rightarrow3^x=9\)
\(\Rightarrow3^x=3^2\)
\(\Rightarrow x=2\)
3x−1+3x+3x+1=39<=>3x:3+3x+3x.3=39<=>3x.13+3x.1+3x.3=39<=>3x.(13+1+3)=39<=>3x.133=39<=>3x=39:133<=>3x=9<=>3x=32<=>x=2
3x−1+3x+3x+1=393x−1+3x+3x+1=39
⇒3x.(13+1+3)=39⇒3x.(13+1+3)=39
MÌnh ko biết kiểu gì mình làm rồi nhưng nó lại ko hiện lên , nó chỉ hiện mỗi câu nói thôi
3x−1+3x+3x+1=393x−1+3x+3x+1=39
⇒3x.(13+1+3)=39⇒3x.(13+1+3)=39