How do you solve 70 -7•7

Adepartment store purchases screen-printed t-shirts at a cost of $5 per shirt. they mark up the price 150% (making the selling price 250% of the store's purchase price) and put them on the sales floor. every month that a t-shirt doesn't sell, the store reduces the selling price by 25%.

41/17 as a decimal rounded to the nearest hundredth

Find the slope of the line passing through a pair of points