Heather has 509 in her savings account. she withdraws 20 per week for gas. write an equation heather can use to see how many weeks it will take her to have a balance of 220.

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

Someone answer this asap rn 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)) =

I'm confused on this could anyone me and show me what i need to do to solve it.