Alexis received an 85, 89, and 92 on three tests. what is the minimum grade alexis can score on the fourth test in order to have an average of at least 90?

Can someone me and plz do the problem

What is the simplified form of (3.25x10^3)(7.8x10^6) written in scientific notation?

Someone answer asap for ! a discount store’s prices are 25% lower than department store prices. the function c(x) = 0.75x can be used to determine the cost c, in dollars, of an item, where x is the department store price, in dollars. if the item has not sold in one month, the discount store takes an additional 20% off the discounted price and an additional $5 off the total purchase. the function d(y) = 0.80y - 5 can be used to find d, the cost, in dollars, of an item that has not been sold for a month, where y is the discount store price, in dollars. create a function d(c(x)) that represents the final price of an item when a costumer buys an item that has been in the discount store for a month. d(c(x)) =