The 'x' in x^2-7x-30=0 is 4.
See the attached picture.
Answer: It is such a small percentage of the population that would be considered to have fever at that level.
So, it is not appropriate stringent standard.
Step-by-step explanation:
Since we have given that
Mean = 98.20°F
Standard deviation = 0.62°F
If Bellevue Hospital in New York City uses 100.6°F as the lowest temperature considered to be a fever.
So, 
So, using the normal distribution, we first find the value of z.

Since z = 3.87
So, p = 0.0001 =0.1%
So,It is such a small percentage of the population that would be considered to have fever at that level.
So, it is not appropriate stringent standard.
Because if that point is true than everything on that side of the number line is true. Visa versa.