possible solution of 4x + 7y = 3 -500<= x <= 500 , -500 <=y <= 500
are x=6 , y= -3
x=13 , y=-7
x=-1 , y= 1
x= -8 y=5
so x has a gap of 7 units 497/7 = 71 ,, so last term is - 498 ,, ,,,,,,,,,, - 1 , 6 , 13 ,,,,,,,, 496
so we get 143 terms , so our answer is 143