Why must ice cream be cooled below 0 before is freezes?

Joseph haydn pet store offers wide variety of leashes for dogs. the store purchases one popular type of leash from its manufacturer for $4.38 each. joseph haydn pets marks up leashes at a rate of 238% of cost. what is the retail price of the popular leash?

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²

Can someone check if i did this correct. it’s number 4 if you’re wondering.