First step is to find the discounted price. Finding 35% less than the original xx is the same as finding 65% of it, so we multiply by 0.65. Once this is completed we need to find 8% more than that. So we add 8% of xx, which is the same as multiplying by 0.08. Hope this helps :)
You practically answered this one yourself by giving some of the equation we need already filled in. It would look like this: A(t)=500(1.04)^7. Start by taking 1.04 to the power of 7 to get A(t)=500(1.3159). Finish by multiplying to get A(t)=$657.97