The weekly total profit (in hundreds of $) from sales of X spas and Y heaters is approximately by
P ( x, y ) = 12 + 74x + 85y - 3x^2 - 5y^2 - 5xy

Suppose 4 spas and 7 heaters are sold each week.

1. What is the approx effect on profit if the number of units of spas made and sold is increased to 5 (while heater sales remain the same)

2. What is the approx effect on profit if 4 spas and 8 heaters are made and sold?