The rate of a chemical reaction varies, depending on the initial amount of a certain compound. In general, the reaction rate, v, can be expressed by the following formula, where k is a positive constant, and a is the initial amount of the compound.
v(x)=kx(a-x)
the positive constant, k, for one such reaction, is 0.9, and the initial amount of the compound, a, is 14. For what value of x is the rate a maximum?

3. solve the given inequality and graph the solution on a number line.

Match the scale and the actual area to the area of the corresponding scale drawing. scale: 1 inch to 4 feet actual area: 128 square feet scale: 1 inch to 7 feet actual area: 147 square feet scale: 1 inch to 8 feet actual area: 256 square feet scale: 1 inch to 5 feet actual area: 225 square feet area of scale drawing scale and actual area scale drawing area: 3 square inches arrowright scale drawing area: 8 square inches arrowright scale drawing area: 4 square inches arrowright scale drawing area: 9 square inches arrowright

How is this equation completed? i cannot find any examples in the book.