Question

Tìm x biết:  3^x+2+3^x=270

Answer 1

\(3^{x+2}+3^x=270\)

=> \(3^x\cdot3^2+3^x\cdot1=270\)

=> \(3^x\left(3^2+1\right)=270\)

=> \(3^x\cdot10=270\)

=> \(3^x=270:10=27\)

=> \(x=3\)

Answer 2

3^x+2 + 3^x = 270

=> 3^x  x 3² + 3^x = 270

3^x x(3² + 1) =270

3^x  x 10 = 270

3^x = 27

3^x  = 3³

=> x = 3

Answer 3

3^x+2+3^x = 270 = 3⁵+3³

x+2+x = 5+3

2x + 2 = 8

2x = 8-2

2x = 6

x = 6 : 2

x = 3

Answer 4

\(\downarrow\)

Answer 5

cách nào đúng v ạ