Answer:
x = 4.
Step-by-step explanation:
These are exterior alternate angles which are congruent.
So 21x + 6 = 90
21x = 84
x = 4.
The answer to this question is y=28
Using a linear function, the correct option regarding the situation is given by:
C) 57 ≤ 1.28x + 38 ≤ 87; To stay within the range, the usage should be between 14.8 and 38.3 HCF.
<h3>What is a linear function?</h3>
A linear function is modeled by:
y = mx + b
In which:
- m is the slope, which is the rate of change, that is, by how much y changes when x changes by 1.
- b is the y-intercept, which is the value of y when x = 0, and can also be interpreted as the initial value of the function.
The bill is modeled by a linear function, with an <u>intercept of $38 and a slope of $1.28</u>, hence it is given by:
C(x) = 1.28x + 38
The bill should be between $57 and $87 dollars per month, hence:
57 <= C(x) <= 87.
The values of x are:
C(x) >= 57
1.28x + 38 >= 57
x >= 19/1.28
x >= 14.8.
C(x) >= 87
1.28x + 38 >= 87
x >= 49/1.28
x >= 38.3.
Hence option C is correct.
More can be learned about linear functions at brainly.com/question/24808124
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