Can someone help me with this question??

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)

Bobs burgers bam has a special deal of 4 hamburgers for $6. at that rate, how much should it cost to buy 3 hamburgers?