If multiply my number by 4, add -4 to the product, and then take 1/3 of the sum, the result is -6. what is my number. show work

Given the following sampling distribution of one mean with a sample size 49, from a normally distributed population,find the population standard deviation, o.79828588912497

Ivan and jeff buy a package of 8 pens for $4.00. ivan wants 5 of the pens, and jeff wants 3.how much should each student pay?

How do you use the elimination method for this question? explain, because i really want to understand!