Which relation is a function?

Which problem could be  solved  by evaluating the expression  7×(−3)7×-3?

Hunter designs two flags for his adventure club. what is the length of the base, x, of the larger flag? enter your answer, as a decimal, in the box.

Ricardo ran the 400 meter race 3 times his fastest time was 54.3 seconds his slowest time was 56.1 seconds if his average time was 55.0 seconds what was his time for the third race