Distance between (5,-5) and (8,-8)

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 gcf of 20c^3-5c^4+30c^6

28 x 12 + 34 = ? it's for a test that if i fail on i will not proceed into the honor roll society i always dreamed of!me! worth 50 !