Astudent finds the slope of the line between (20,2) and (1,17). she writes 1-17/1-20 what mistake did she make?

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.