Answer:
i) The maximum height  of the ball 'x' = 1.5 seconds
ii)  The maximum height  = 42
 Step-by-step explanation:
Step(i):-
Given h(x) = - 16 x² + 48 x +6  ...(i)
Differentiating equation (i) with respective to 'x'
[tex]h ^{l} (x) = - 16 (2 x) +48 (1)[/tex] Â ...(ii)
Equating Zero
- 3 2 x + 4 8 = 0
- 32 x = - 48
  x = 1.5
step(ii):-
The maximum height of the ball 'x' = 1.5
Again Differentiating equation (ii) with respective to 'x'
[tex]h ^{ll} (x) = - 16 (2 x) < 0[/tex]
The maximum height 'x' = 1.5
h(x) = - 16 x² + 48 x +6 Â
h(1.5) = - 16 (1.5)² +4 8 (1.5) +6
     =  42
The maximum height at x = 1.5 is  = 42
Final answer:-
i) The maximum height  of the ball 'x' = 1.5 seconds
ii)  The maximum height  = 42