Explain why the average temperature change was -5 per hour

At a sale this week, a desk is being sold for $213. this is a 29% discount from the original price. what is the original price?

Find an equation of the line perpendicular to the graph of 28x-7y=9 that passes through the point at (4,1)

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?