Please Help me I am very confused on both of these questions. It is due by midnight. Round each measure to the nearest tenth. Thanks for the help!

Aresearch company wants to test the claim that a new multivitamin to improve short term memory. state the objective of the experiment, suggest a population, determine the experimental and control groups, and describe a sample procedure.

Two cyclists 84 miles apart start riding toward each other at the samen time. one cycles 2 times as fast as the other. if they meet 4 hours later what is the speed (in miles) of the faster cyclists

The roots of the function f(x) = x2 – 2x – 3 are shown. what is the missing number?