Simplify these 3 expression mats please, I want to sleep I will give you brainliest if you answer first, please

Y=4x^2+x-1 solve using quadratic formula

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%.

How do you use the elimination method for this question? explain, because i really want to understand!