Mark needs 3 ⅛ pounds of seed to fill the birdfeeders in his backyard, but he only has 1 ½ pounds of seeds. How much more seed does he need to buy?

Quick translate "x is 12 units from 20" into an equation. what are the values of x being described? if you can answer any of my other questions that'd be great too

Which system of linear inequalities is represented by the graph?

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9