\(3^x+3^{x+1}+3^{x+2}=243.39\)
\(3^x.\left(1+3^1+3^2\right)=243.3.13\)
\(3^x.\left(1+3+9\right)=\left(243.3\right).13\)
\(3^x.13=729.13\)
\(3^x=729.13\div13\)
\(3^x=729\)
\(3^x=3^6\)
\(x=6\)
\(3^x+3^{x+1}+3^{x+2}=243.39\)
\(\Leftrightarrow3^x+3^x.3+3^x.3^2=9477\)
\(\Leftrightarrow3^x\left(1+3+3^2\right)=9477\)
\(\Leftrightarrow3^x.13=9477\)
\(\Leftrightarrow3^x=9477:13\)
\(\Leftrightarrow3^x=729\)
\(\Leftrightarrow3^x=3^6\)
\(\Leftrightarrow x=6\)
~ Rất vui vì giúp đc bn ~
\(3^x+3^{x+1}+3^{x+2}=243\cdot39\)
\(\Leftrightarrow3^x\left(1+3+3^2\right)=3^5\cdot3\cdot13\)
\(\Leftrightarrow3^x\cdot13=3^6\cdot13\)
\(\Leftrightarrow3^x=3^6\Rightarrow x=6\)
\(3^x+3^{x+1}+x^{x+2}=243\cdot39\)
\(3^x+3^x\cdot3+3^x\cdot3^2=9477\)
\(3^x\left(1+3+3^2\right)=9477\)
\(3^x\cdot13=9477\)
\(3^x=9477\text{ : }13\)
\(3^x=729\)
\(3^x=3^6\)
\(\Rightarrow\text{ }x=6\)
