How can i solve this equation 6+7x=55

You could solve it with these two steps:

             #1).  Subtract 6 from each side of the equation.
and then
             #2). Divide each side by 7.

If you'll do that, the solution will be right there on the paper in front of you.
It'll begin with "x =", and right after that will be the value of 'x'.

  6+7x=55
-6         -6
 7x=49
7x/7 and 49/7

x=7

The year before the 10s so it was like when caveman were alive