The first step is to remember the properties of logarithms
One of them are the addtive property:
When two logarithms have the same base and they are summing between them, their arguments can be multiplied.
[tex]\log_a(x)+\log_a(y)=\log_a(x*y)[/tex]
Now solve your problem:
[tex]\log_77+\log_7343=\log_7(7*343)=\log_7(2401)[/tex]
