\(3^x+3^{x+2}=810\)
\(\Leftrightarrow3^x\left(1+3^2\right)=810\)
\(\Leftrightarrow3^x\cdot10=810\)
\(\Leftrightarrow3^x=81\)
\(\Leftrightarrow x=4\)
\(3^x+3^{x+2}=810\)
\(\Rightarrow3^x+3^x.3^2=810\)
\(\Rightarrow3^x.\left(1+3^2\right)=810\)
\(\Rightarrow3^x.10=810\)
\(\Rightarrow3^x=81\)
\(\Rightarrow3^x=3^4\)
\(\Rightarrow x=4\)
Vậy x = 4
3x+3x+2=810
3x+3x.32=810
3x.(32+1)=810
3x.10=810
3x=81
3x=34
vậy x=4
chúc bạn học tốt(like mình nha)
\(3^x+3^{x+2}=810\)
\(3^x.1+3^x.3^2=810\)
\(3^x\left(2^2+1\right)=810\)
\(3^x.10=810\)
\(3^x=810:10\)
\(3^x=81\)
\(3^x=3^4\)
\(\Rightarrow x=4\)
