Best Windows is a small company that installs windows. Its cost structure is as follows: Use (a) the equation method and (b) the contribution method to calculate operating income if Best installs 4,000 windows. Use (a) the Equation method to calculate operating income if Best installs 4,000 windows. Begin by determining the formula to calculate the operating incorne using the equation method. Then, calculate the operating income (Abbreviafion used Selling price, VCU = Varable cost per unit, Q= Quantity of units sold, Next, use (b) the contribution method to calculate operating income if Best installs 4,000 windows. Begin by determining the formula to calculate the operating income using the contribution method. Then, calculate the operating income