(a)[2]
Write $3y^2 - 12y - 15$ in the form $3(y + a)^2 + b$, with $a$ and $b$ as constants.
(b)[3]
Hence find the exact solutions for the equation $3x^4 - 12x^2 - 15 = 0$.
Mathematics 9709 · AS & A Level · Quadratics
Quadratics — practice question
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Valid completed square form $3(y-2)^2-27$ or identifying $a=-2$, $b=-27$.” …
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