So the first thing you are going to want to do is isolate the x variable onto one side.
To do that you want to add 1/10 to each side since there is a -1/10 on the side with the 4/5x.
That will leave you with 4/5x=4/10.
The next thing you want to do is get rid of the fraction with the x. To do that you will need to multiply each side with the reciprocal of 4/5. The reciprocal is the reverse of the fraction. In this case that would be 5/4.
Your equation would look like this 5/4*4/5x=4/10*5/4
After you simplify that it leaves you with x=1/2.
Your final answer is x=1/2.
If you have any questions let me know. I hope this helps.