Question

3^x+2-5.3^x=36 

tim x

giup minh vo cac ban minh dang can gap nha 

cam on cac ban nhieu

Answer 1

3^x+2-5.3^x=36

3^x(3^2-5)=36

3^x.4=36

3^x=9

x=2

Answer 2

\(3^{x+2}-5\cdot3^x=36\)

\(3^x\cdot3^2-5\cdot3^x=36\)

\(3^x\left(3^2-5\right)=36\)

\(3^x\left(9-5\right)=36\)

\(3^x\cdot4=36\)

\(3^x=36:4\)

\(3^x=9\)có \(3^2=9\)

\(\Rightarrow x=2\)

\(\Rightarrow x\in\left\{2\right\}\)