91Ó°ÊÓ

Factor each of the following expressions as completely as possible. If an expression is not factorable, say so. $$x^{2}-8 x-20$$

The length of a rectangular garden is 5 more than its width and is surrounded by a uniform path 2 ft wide. If the total area of the garden plus path is 300 sq ft, find the width of the garden.

If a rocket is shot straight up into the air from ground level with an initial velocity of \(240 \mathrm{ft}\) per second, its height \(h\) (in feet) above the ground \(t\) seconds after it is launched is given by the equation \(h=240 t-16 t^{2} .\) How long does it take for the rocket to reach a height of 800 ft? Explain the significance of your answer(s).

Factor each of the following expressions as completely as possible. If an expression is not factorable, say so. $$a^{2}+13+14 a$$

Simplify the expression and express your final answer with positive exponents only. $$\left(x^{-3}\right)^{-4}$$

How much pure acid must be added to 40 liters of a \(20 \%\) acid solution to raise it to a \(25 \%\) acid solution?

Express the given number in scientific notation. $$0.00431$$