The Function having highest Degree of Four given here is :
As the given function has highest degree of four, it has maximum of four roots.
As complex and Irrational root occur in pairs, so There are many possibilities
1. Two Complex or Irrational + Two Real
2. Four real roots
3.All roots are complex or irrational
By looking at the options described below, it means it has four real roots.
It will cut X axis at four points.
With the help of Desmos you can directly find the solution of this problem, but without desmos Graphing, we first have to check by Taking different points on the curve whether graph of function described here is correct or not, i.e by method of increasing and decreasing formula of a function.The method to check is
If there are two points on the curve i.e 
1. 
Increasing Function.
2. 
Decreasing Function.
Option (4) is true .
Answer:
A 90% confidence interval for the mean number of letter sounds identified in one minute is: (30.84, 37.34).
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
That is z with a pvalue of 
, so Z = 1.645.
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 34.09 - 3.25 = 30.84.
The upper end of the interval is the sample mean added to M. So it is 34.09 + 3.25 = 37.34.
A 90% confidence interval for the mean number of letter sounds identified in one minute is: (30.84, 37.34).
part A)
we know that for every 1000 ft the temperature drops by 1.3.
so after 1000ft up it went down by 1.3(1)
2000ft up it went down by 1.3(2) or 2.6
3000ft up it went down by 1.3(3) or 3.9
after 10000 up it went down by 1.3(10) or 13.
part B)
well, the current temperature on the ground where the plane is sitting is -2.8°F, after 10000ft it dropped by 13°, so the temperature will just be -2.8 - 13 = -15.8°F.
