Question

3^x+3^x+2=810

Answer 1

 

3^x+3^x+2=810

\(3^x\).1 + \(3^x\).\(3^2\) =810

\(3^x\) .(1 + \(3^2\) )=810

\(3^x\) .10 =810

\(3^x\) =810 :10

\(3^x\) = 81

\(3^x\) =\(3^4\)

\(\Rightarrow\) 4

Vậy x=4

 

Answer 2

\(3^x+3^{x+2}=810\)

\(\Rightarrow3^x+3^x.3^2=810\)

\(\Rightarrow3^x.\left(1+3^2\right)=810\)

\(\Rightarrow3^x.10=810\)

\(\Rightarrow3^x=81\)

\(\Rightarrow3^x=3^4\)

\(\Rightarrow x=4\)

Vậy \(x=4\)

Answer 3

\(3^x+3^{x+2}=810\)

\(3^x.1+3^x.3^2=810\)

\(3^x.\left(1+3^2\right)\) \(=810\)

\(3^x.10=810\)

\(3^x=810:10\)

\(3^x=81\)

\(3^x=3^4\)

\(\Rightarrow x=4\)

Vậy \(x=4\)