40x + 1000 = 7420 ...subtract 1000 from both sides
40x = 7420 - 1000
40x = 6420 ...divide both sides by 40
x = 6420/40
x = 160.5 <== he worked 160.5 hrs
** he made 40 per hr (x).....add the 1000 for the special project.....and thats gonna equal his pay of 7420.