Question

\(9^x.81^x=3^{2010}\)

Answer 1

\(9^x.81^x=3^{2010}\)

\(\Leftrightarrow9^x.\left(9^2\right)^x=\left(3^2\right)^{1005}\)

\(\Leftrightarrow9^x.9^{2x}=9^{1005}\)

\(\Leftrightarrow9^{3x}=9^{1005}\)

=> 3x = 1005

=> x = 335

Answer 2

Từ đề bài ta có:

==> 9^x.9^2x = 9¹⁰⁰⁵

==> x+2x=1005

3x=1005

x=1005:3=335