Question

Which of the following is the sketch of y2 – 8y – 12x – 8 = 0?

Answer 1

it looks like a parabola which is concave right...



\[y^2 - 8y = 12x + 8\]

complete the square

\[y^2 - 8y + 16 = 12x +8 + 16\]

which can be factorised to

\[(y -4)^2 = 12(x +2)\]

the general form is

\[(y -k)^2 = 4a(x -h)\]

the vertex is (h, k) and focal length is a

hope this helps