I have deleted the link you posted, as that website is diametrically opposed to the philosophy of Math Help Boards, and even, in my opinion, utterly unethical. May that website die a thousand deaths. That website will not help you understand math in any way. If you want to understand math, then you've come to the right place! What we do here is quite different. You post problems, at most two per thread, and you show us the progress you've made on them, as well as explaining exactly where you're stuck. Then we come along and help you get unstuck, just at that one place. We do not hand out answers to you, because that won't help you understand. Math simply isn't a spectator sport. You have to pull the weight yourself.
You'll realize this once you come to test-time, and you don't have the resources of the other website at your disposal. Our way is slower, admittedly (so make sure you're asking questions well in advance! We're all volunteers here.), but it will help you understand far better.