To 15 a) Plug in x=-2 into the equation of the function. Then b = f(-2).

Keep in mind that and that . You'll find that your calculated value of b must be wrong.

To 15 b) The function f is increasing in P if the gradient of f in P is positive. Therefore determine the first derivation of f and plug in x = -2. If f'(-2) > 0 then the statement is true.

EDIT: Could you please indicate which of the questions are not clear to you?