The axis of symmetry is 2 and the vertex is (2, 4).
Answer:

Step-by-step explanation:
We start off with 3.2n + 13.3 = 26.1.
We need to get n by itself.
Subtract 13.3 from both sides.


We end up with: 
Divide 3.2 on both sides to get n by itself.

Use slander and search textbook up it will show up with answers
Since the data is insufficient. Let us denote that n1 = 100, n2 = 100X1 = 38. X2 = 40
So looking for the p value:
p = (38+ 40) / (100 + 100) = 0.39
z = (38/100 - 40/100)/√ (0.39*(1-0.39)*(1/100 + 1/100))= -0.2899
P-value = P (|z| > 0.2899) = 0.7718