I’m confsued…can someone help :)

Anewborn baby had about 26,000,000,000 cells. an adult has about 4.94 times 10 to the 13 power cells. how many times as many cells does an adult have than a newborn

Sara bought a pair of pants that were on sale for 30 percent off of the original price. if the original price of the pants was $29, what was the sales price of the pants?

Iam trying to solve a linear equation for the shoe size of someone 84" tall taking into consideration example 1 is 69" tall with a shoe size of 9 and example 2 is 72 inches tall with a shoe size of 11. i understand that the equation should be y=mx+b and that on the graph the answer is (3,2) but i just don't understand how to create the equation to solve for 84-inches and 60-inches tall questions. after two days, i need .