a) \(3^x+3^{x+2}=810\)
\(=>3^x+3^x\cdot9=810\)
\(=>3^x\left(1+9\right)=810\)
\(=>3^x\cdot10=810\)
\(=>3^x=810:10=81\)
\(=>3^x=3^4\)
\(=>x=4\)
a) \(3^x+3^{x+2}=810\)
\(\Leftrightarrow3^x\left(1+3^2\right)=810\)
\(\Leftrightarrow3^x\cdot10=810\)
\(\Leftrightarrow3^x=81\)
\(\Leftrightarrow x=4\)
b)\(2^x+2^{x+3}=144\)
\(\Leftrightarrow2^x\left(1+2^3\right)=144\)
\(\Leftrightarrow2^x\cdot9=144\)
\(\Leftrightarrow2^x=16\)
\(\Leftrightarrow x=4\)
a) \(3^x+3^{x+2}=810\)
\(\Rightarrow3^x+3^x.3^2=810\)
\(\Rightarrow3^x.\left(1+3^2\right)=810\)
\(\Rightarrow3^x.10=810\)
\(\Rightarrow3^x=81\)
\(\Rightarrow3^x=3^4\)
\(\Rightarrow x=4\)
Vậy x = 4
b) \(2^x+2^{x+3}=144\)
\(2^x+2^x.2^3=144\)
\(2^x.\left(1+2^3\right)=144\)
\(2^x.9=144\)
\(2^x=144:9\)
\(2^x=16\)
\(2^x=2^4\)
\(\Rightarrow x=4\)
Vậy x = 4
b) \(2^x+2^{x+3}=144\)
\(=>2^x+2^x\cdot8=144\)
\(=>2^x\cdot\left(1+8\right)=144\)
\(=>2^x\cdot9=144\)
\(=>2^x=144:9=16\)
\(=>2^x=2^4\)
\(=>x=4\)
a)3x+3x+2=810
3x.1+3x.32=810
3x.(1+32)=810
3x.10=810
3x=81=3
Vậy x=4
b)2x+2x+3=144
2x.1+2x.23=144
2x.(1+23)=144
2x.9=144
2x=16=24
Vậy x=4
