The answer is
8x^4-10x^3-3x^2
The domain is talking about the "range" of the horizontal axis therefore you will be focusing on the x-intercepts.
The answer will be All non-negative real numbers less than or equal to 18
because the x-intercepts lies at 0 and 18. The answer makes sense because the furthest you can go is 18 ft and the closest you could go is 0 ft. The "all non-negative real numbers" puts a restriction on the least distance it could travel so that means that it stops at 0 ft because if you go any further, you will end up in the negatives and it clearly states "non-negative".
the maximum height is the y-value of the vertex.
h(x) = -2x² + 20x + 48
<em> a=-2, b=20, c=48</em>

h(5) = -2(5)² + 20(5) + 48
= -50 + 100 + 48
= 50 + 48
= 98
Answer: 98 meters
Area = πr² = π(8)² = 201.06 in²
Answer: 201.06 in²