\(3^{x+2}+3^x=270\\ =>3^x.3^2+3^x=270\)
\(=>2.3^x=270:9=30\)
\(=>3^x=30:2=15\)
\(=>3^x=15\)
Có sai đề ko bn ???
\(3^{x+2}+3^x=270\)
=> \(3^x.3^2+3^x=270\)
=> \(3^x.\left(3^2+1\right)=270\)
=> \(3^x.10=270\)
=> \(3^x=27=3^3\)
=> \(x=3\)
\(3^{x+2}+3^x=270\)
\(3^x.3^2+3^x=270\)
\(3^x.\left(3^2+1\right)=270\)
\(3^x=270:10\)
\(3^x=27\)
\(3^x=3^3\)
\(\Rightarrow x=3\)
#Trieu van làm đúng rồi
Mk làm sai đừng để ý
~ Học tốt ~
\(3^{x+2}+3^x=270\)
\(3^x\left(3^2+1\right)=270\)
\(3^x\cdot10=270\)
\(3^x=270\text{ : }10\)
\(3^x=27\)
\(3^x=3^3\)
\(\Rightarrow\text{ }x=3\)
Trả lời :
\(3^{x+2}+3^x=270\)
\(3^x\left(3^2+1\right)=270\)
\(3^x\cdot10=270\)
\(3^x=270\text{ : }10\)
\(3^x=27\)
\(3^x=3^3\)
\(\Rightarrow\text{ }x=3\)
