What is a word problem for 8x=48

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.1. (round your answers to four decimal places.) (a) if the distribution is normal, what is the probability that the sample mean hardness for a random sample of 8 pins is at least 51?

Nick and nora are married and have three children in college. they have an adjusted gross income of 47,400. if their standard deduction is 12,600 itemized deductions are 14,200 and they get an exemption of 4000 for each adult and each dependent what is their taxable income

Which of the expressions (on the photo document i inserted) together represent all solutions to the following equation? 8cos(12x)+4=-4 *the answer should be in degrees.* > i would like for someone to explain the process to find the solutions for this.