I have a fair variety of problems that I am having some issues with--most I have worked out but need confirmation on, others I have no real idea what to do with.

The ones I need todouble checkare:

(1)

Assuming that none of the solutions are undefined,simplify each of the following:

(a)

My answer: Either abc or ab(I'm not too sure which, though I am leaning towards "ab")

(b)

My answer: or

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(2)

Simplify:

(a)

My answer:

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(3)

If you arehfeet above the earth's surface, the distance,d, that you can see is approximatelyd(in miles)= .

Suppose you are on the roof of a building 900 ft. tall. how far can you see?(calculate to two decimal places)

My answer: so Thus, I can see for 36.74 Mi.

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(4)

According to Descartes' Rule of Signs, (a) how many positive real roots does each of the following have? (b) how many negative roots?

(1)

My answer:

(a):1

(b):0

(2)

My answer:

(a):0

(b):1

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Now for the ones I have no idea about.

(1)

Solve the equation , if -2 is a root.

(I have tried to solve this one but when I do synthetic division on it I get the equation: which I don't think will work)

(2)

Find the dimensions of a rectangleawith the greatest area whose perimeter is 30 feet.

(I got nothing--I'm totally confused as to what to do with this one.)

Thank you!