Using a linear function, the inequality is given by: 69.5 + 5x < 90.
The solution is: x < 4.1.
What is a linear function?
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.
In this problem, we have that:
- The y-intercept is the flat cost of $69.50.
- The slope is the cost per gigabyte of $5.
Hence the cost of using x gigabytes is:
C(x) = 69.5 + 5x.
The cost has to be under 90, hence the inequality is:
C(x) < 90
69.5 + 5x < 90.
Then the solution is:
5x < 90 - 69.5.
x < 20.5/5
x < 4.1.
More can be learned about linear functions at https://brainly.com/question/24808124
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