Hey StephenSkinner.

I'm going off Wikipedia for definitions, so if that is wrong then please inform us.

Standard form is y = -3x^2 + 24x - 46

Vertex point is (4,2)

Maximum point is y = 2 given x = 4.

For d I got the same (as long as its SQRT(2/3) and not sqrt(2)/3) and y-int is -46.

Same as you for e.

Very well done.