when doing substitution,you must make one a subject,which is y in this case.To make y the subject,you must move -2y to 4x to make the y positive,that leaves us with 2y+4x=5.Now move the 4x to 5 to make 2y=5-4x.Lastly,to make y the subject,divide both side by 2 to remove the 2 from the y, which leaves us with y=5-4x/2
