What is the least common multiple of 3 and 9

When you answer this can you explain

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.

Graph the system of equations. {6x−4y=−244x−8y=−32 use the line tool to graph the lines.