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.