HELP ASAP! THREE MATH QUESTIONS 20 POINTS FOR REWARD

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

Ellen makes and sells bookmarks. she graphs the number of bookmarks sold compared to the total money earned. why is the rate of change for the function graphed to the left?

What is the equation of a line that passes through points (0, 4) and (-4,-8)?