Can you find the value of x in the problem below? http://t.co/DPiWO1qIix pic.twitter.com/SDbUDqEG8T

— Khan Academy (@khanacademy) 12 พฤษภาคม 2015

4x = x +45
4x = 45 + x
4x  - x = 45
3x  =  45
x = 45/3
x = 15