How can you determine whether a sum of numbers, such as 127 + 38, is even or odd without building a tile model or computing the sum?

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.