Let's start with fractions:
 

Solve  
 
2/7 + 3x = 5

This thing would be a lot easier to solve without this fraction... 
So, let's make that happen!

If we multiply both sides by 7, we'll be able to ditch that fraction!

Check it out:

7 ( 2/7 + 3x ) = 7 ( 5 )  which gives   ((7)(2)/7 + 7(3x) = 7(5)  which gives a regular equation  2 + 21x = 35  ditch the 2...   2 - 2 + 21x = 35 - 2  which gives  21x = 33  ditch the 21...  21x/21 = 33/21  which gives  x = 33/21 = 11/7

I'll let you check it.