Question

\(3^x+3^{x-1}+3^{x+2}=117\)

Answer 1

\(3^x+3^{x-1}+3^{x-2}=117\)

\(3^x\times\left(1+\frac{1}{3}+\frac{1}{9}\right)=117\)

\(3^x\times\frac{13}{9}=117\)

\(3^x=117\div\frac{13}{9}\)

\(3^x=117\times\frac{9}{13}\)

\(3^x=81\)

3^x = 3⁴

x = 4

 

Answer 2

\(3^x+3^{x-1}+3^{x+2}=117\)

\(=3^x+3^x.3+3^x.3^2=117\)

\(3^x.\left(1+3+3^2\right)=117\)

\(3^x=9\)

\(3^x=3^2\)

\(=>x=2\)

Chúc bạn học tốt!

Answer 3

3^x(1 +1/3 + 9) =117

3^x = 117.3/31= 351/31

x =? chắc sai đề

Answer 4

Nhầm đề rồi mấy bạn ơi.