( please help ) write the equation of the line below

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%.

Find the value of x that will make l ll m

25 ! what is the value of x? enter your answer in the box. x =