6x+x=511:59+31
7x=25+3
7x=28
x=28/7
x=4
\(\Rightarrow7x=5^{11-9}+3\)
\(\Rightarrow7x=5^2+3\)
\(\Rightarrow7x=28\)
\(\Rightarrow x=\frac{28}{7}\)
6x+x=511:59+31
6x+x=52+3
6x+x=25+3
6x+x=28
x+x=28:6
2x=14/3
x=7/3
\(6x+x=5^{11}:5^9+3^1\)
\(7x=28\)
\(x=28:7\)
\(x=4\)
Vậy x = 4