Simplify using positive exponents only (2x^3y^3)^-2(4^-1x^5y^-2)^2

Answer question above and explain each step : )

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%.

Aline has a slope of 1/4 and passes through point (0.4,-1/2). what is the value of the y-intercept?