20pts!!! When answering the following questions, consider the system of all polynomial equations and the system of all rational equations.

Which systems are closed under addition? If either system is not closed under addition, provide a counterexample.

Asmall business produces and sells balls. the fixed costs are $20 and each ball costs $4.32 to produce. each ball sells for $8.32. write the equations for the total cost, c, and the revenue, r, then use the graphing method to determine how many balls must be sold to break even.

Select the graph of the solution. click until the correct graph appears. |x| = 3

2.5 milligrams is equivalent to how many grams