Mathematics 9709 · AS & A Level · Functions

Functions — practice question

The rule for $f$ is $f(x) = 3x + 1$ when $x \leq a$, where $a$ is constant. The rule for $g$ is $g(x) = -1 - x^2$ when $x \leq -1$.
(a)[2]

Find the greatest value of $a$ for which the composite function $fg$ can be formed.

(b)[3]

When $a = -1$, solve $fg(x) + 14 = 0$.

(c)[4]

When $a = -1$, find all values of $x$ that satisfy $fg(x) \leq -50$.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Solve $3x+1\le -1$

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