expert please answer that what is the method and what are the reasons for each and every step.....
Answer this with a help of video only......??

Dear student, You just need to remember that you can add or subtract only like terms. For eg: you can add a term having x with another term having x only. You cannot add x with 2. And in this question you have simply separated the terms with x on the left hand side of '=' and constant terms on the right hand side. And equate them to get the value of x in the last step. Hope this clears your doubt. Regards