The question asks for the optimal number of calculators, so my variables will stand for that:
x: number of scientific calculators produced
y: number of graphing calculators produced
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Since they can't produce negative numbers of calculators, I have the two constraints, x > 0 and y > 0. But in this case, I can ignore these constraints, because I already have that x > 100 and y > 80. The exercise also gives maximums: x < 200 and y < 170. The minimum shipping requirement gives me x + y > 200; in other words, y > –x + 200. The profit relation will be my optimization equation: P = –2x + 5y. So the entire system is:
P = –2x + 5y, subject to:
100 < x < 200
80 < y < 170
y > –x + 200
The feasibility region graphs as: