Answer:
Yes, this is a valid inference because she took a random sample of the neighborhood.
Step-by-step explanation:
As her survey was non bias and completely random and she found that 15% of the families would participate in the event. She claims that 15% of the neighborhood families would be expected to participate in the sports event. So, yes, this is a valid inference because she took a random sample of the neighborhood.
Answer:
f(x) = -(x-4)^2 + 5
Step-by-step explanation:
The function 
is a quadratic function. Its graph looks like a parabola. The graph has a vertex of (4,5) and opens up downward.
Proving that 
for all x:
