Hello, stepho_145!

Here's the first one . . .

1. **Minimizing Construction Costs**

The UNICO department store has decided to enclose an 800 ft² area

outside the building. One side will be formed by the external wall of the store;

two sides will be made of pine boards, and the fourth side will be galvanized steel fencing.

If the pine boards cost $6/ft and the steel fencing costs $3/running foot,

determine the dimensions of the enclosure that can be erected at minimum cost. Code:

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x

The area will be 800 ft².

We have: . .[1]

The cost will be: .

Hence, the total cost is: . .[2]

Substitute [1] into [2]: .

Therefore: .

. . and **that** is the function we must minimize.

*Go for it!*