4times what number get me close to 84 without going over

Answer this 30 points and brainliest!

Choose the point slope form of the equation below that represents the like that passes through the points (-6,4) and (2, 0)

Thompson and thompson is a steel bolts manufacturing company. their current steel bolts have a mean diameter of 127 millimeters, and a variance of 36. if a random sample of 35 steel bolts is selected, what is the probability that the sample mean would differ from the population mean by greater than 0.5 millimeters? round your answer to four decimal places.