quadratic question hard

[nocturne lynx]

Question:
y = f(x) produces a parabola with maximum at (4 , 15)
it also crosses x axis at (0 , -17)
find roots of f(x)

i tried to work backwards using completing the square and got f(x) as:
-(17/31)x^2 + (136/31)x - 17 which seems very wrong to me. any explanation is appreciated.

[oak radish]

so this is what a level maths is.........

welp im dead

[nocturne lynx]

☹️

[naive ingot]

a bit late but

is it 6.73 and 1.26

do u have the asnwer

[azure siren]

what was the answer / where did you get the Q from

[brittle ferry]

I mean you cover most of the basic of this topic at gcse parabola just means quadratic

[brittle ferry]

how does it cross the x axis at 0, -17

do you mean the y?

[uncut jay]

yeah