Answer: 
Step-by-step explanation:
Given
The highest temperature recorded is 
The lowest temperature recorded is 
The amount of change between the high and the low temperatures is

The function (fg)(x) is a composite function
The value of the function (fg)(x) is 2x^3 + 7x^2 - 19x - 20
<h3>How to determine the function (fg)(x)?</h3>
The functions are given as:
f(x) = 2x^2 - 3x - 4 and g(x) = x + 5.
To calculate (fg)(x), we make use of
(fg)(x) = f(x) * g(x)
So, we have:
(fg)(x) = (2x^2 - 3x - 4) * (x + 5)
Expand
(fg)(x) = 2x^3 - 3x^2 - 4x + 10x^2 - 15x - 20
Collect like terms
(fg)(x) = 2x^3 - 3x^2 + 10x^2 - 4x - 15x - 20
Evaluate
(fg)(x) = 2x^3 + 7x^2 - 19x - 20
Hence, the function (fg)(x) is 2x^3 + 7x^2 - 19x - 20
Read more about composite function at:
brainly.com/question/10687170
90. Add the zero in front of the 9.
The equation given in the question has to be answered to the nearest tenth. The only thing that one should be careful about is the cross multiplication part. Other than that there is no difficulty in the given problem. Now let us get down to the equation in the question.
15/30 = n/34
30 * n = 15 * 34
30n = 510
n = 510/30
= 51/3
= 17
So the value of the unknown variable "n" comes out to be 17.