Mathematics 9709 · AS & A Level · Quadratics

Quadratics — practice question

The function $f$ has the rule $f(x) = -2x^2 - 8x - 13$ for $x < -3$.

(a)[2]

Express $f(x)$ in the form $-2(x + a)^2 + b$, with $a$ and $b$ both integers.

(b)[1]

Find the range of the function $f$.

(c)[3]

Find an expression for $f^{-1}(x)$.

Worked solution & mark scheme

This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “States the result $f(x)=-2(x+2)^2$” …