4x - y = 1 slope intercept form

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%.

597008.439431 to the nearest thousand

Arectangular garden measures 5m by 7m. both dimensions are to be extended by the same amount so that the area of the garden is doubled. by how much should the dimensions increase, to the nearest tenth of a metre?