How do u solve for x please and thank you!! Need ASAP

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%.

Answer for 10 points show work you guys in advanced < 3

Which is an x-intercept of the graphed function? (0, 4) (–1, 0) (4, 0) (0, –1)