Mathematics 9709 · AS & A Level · Quadratics

Quadratics — practice question

(a)[2]

Express $9x^2 - 36x + 8$ in the form $p(x + q)^2 + r$, where $p$, $q$ and $r$ are constants.

(b)[1]

Hence determine the values of the constant $k$ for which the equation $9x^2 - 36x + 8 = k$ has no real roots.

(c)[2]

Find the exact roots of the equation $9x^2 - 36x + 8 = -15$.

Worked solution & mark scheme

This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: So the constants are $p=9$, $q=-2$, and $r=-28$.

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