The answer would be 6. Why? It's because of the 24%. You have to change the 24 into 0.24. If you left it alone, the process would be confusing. Changing it into a decimal is much easier. After you changed the percent into a decimal, multiply the 25. You should get 6 as an answer.
4(5x+1)(5x-1) = 0
1. Take out the GCF (in this case, 4)
4(25x^2-1) = 0
2. This can be further factored. Factor the values within the parenthesis
4(5x + 1)(5x -1) = 0