Joanne puts 40 bacteria in a petri dish. The population of bacteria is doubling every hour. Which function best represents the situation? (TEKS A.9B-5)

Can someone show me the steps to solve the problem?

Question: what is the value of x 4x-2= (-7) +5x. it would be greatly appreciated if someone could actually explain to me step by step

At the beginning of 1974/75,2 years a man invested #2000 in a bank at 12.5% compound interest, if it degree #650 at the end of each two years to pay his son's school fees, after payment of interest to pay his son's school fees, how much did he have left at the beginning of the 1978/79 school year?