Combine like terms to create an equivalent expression: -3x-6+(-1)

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%.

What is the factored form of the following expressions? d^2 – 13d + 36

Me. i can't figure out this question. give an explanation too. .