Hi i need help again
(I need help on number 9) ty

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.

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

The functions below show the amount of money bella and sweet t had saved after earning money for doing chores. which description best compares the two functions?