Final answer:
To answer part (a), we substitute x with 14 in the equation C = 162.15x - 91, and calculate the cost as $2,179.10. For part (b), we rearrange the equation to solve for x and determine that Jenna took approximately 12 credit-hours when she spent $1854.80.
Step-by-step explanation:
The question requires us to use the linear equation C = 162.15x - 91 to calculate the costs for tuition and fees for a given number of credit-hours at a public college. This equation represents a function where C is the cost in dollars and x is the number of credit-hours.
Part (a)
To determine the cost to take 14 credit-hours, we substitute x with 14 in the equation. The calculation is as follows:
C = 162.15(14) - 91
C = 2270.10 - 91
C = 2179.10
Therefore, the cost to take 14 credit-hours round to the nearest cent is $2,179.10.
Part (b)
To find out how many credit-hours Jenna took when she spent $1854.80, we rearrange the equation to solve for x:
C + 91 = 162.15x
Substituting C with $1854.80:
$1854.80 + 91 = 162.15x
$1945.80 = 162.15x
x ≈ $1945.80 / 162.15
x ≈ 12
Jenna took approximately 12 credit-hours.