To simplify the expression, we'll follow the order of operations (parentheses, exponents, multiplication and division, addition and subtraction) step by step.

Calculate what is inside the parentheses first:
28×5 = 140
25×4 = 100
120÷2 = 60
Add the first two results and then subtract the third:
140 + 100 - 60 = 180

Calculate the expression inside the second set of parentheses next:
28÷14 = 2
420÷140 = 3
Add the two results:
2 + 3 = 5

Now substitute these results back into the original expression:
500 - (180)÷6 - (5)×30
This becomes:
500 - 30 - 150

Finally, calculate the remaining subtraction:
500 - 30 - 150 = 320

Therefore, the simplified expression is 320.