Represent an equation that describe a number less than and equal to 3

Given f(x) = 17-x^2what is the average rate of change in f(x) over the interval [1, 5]?

Weekly wages at a certain factory are normally distributed with a mean of $400 and a standard deviation of $50. find the probability that a worker selected at random makes between $450 and $500

Someone me what is the area of this figure? 18m 18m 8m 16m