The standard form for a two variable equation is ax + by = c , where a,b and c are integers.
rearranging the above equation gives
1/3x + 29 (-29)(-4y) = 4y (-29)(-4y)
1/3x - 4y = -29
3(1/3x) - 3(4y) = 3(-29) multiplying by 3 gives you all integers
x - 12y = -87