A pet store purchases dog collars from a distributor for $6 per dog collar. Th store marked up the price of the dog collars by 35%. What is the selling price of one dog collar?

Three times the sum of a number and seven is negative thirty-six. what is the number?

The figures below are made out of circles, semicircles, quarter circles, and a square. find the area and the perimeter of each figure and give your answers as a completely simplified exact value in terms of π (no approximations).

He mass of a single atom of carbon can be found by dividing the atomic mass (12.01 g) by 6.022 x 10^23. which is the mass of a single carbon atom, correctly written in scientific notation with the correct number of significant figures?