Use the function $y=\frac{3}{2} x-3$ to find the value of $y$ when $x=8$.
We are given the linear function \(y = \frac{3}{2}x - 3\). Our objective is to determine the value of \(y\) for the specific input value \(x = 8\). This is a straightforward substitution problem where we replace the variable \(x\) with its given numerical value and simplify the resulting expression.
To find the value of \(y\) when \(x = 8\), we substitute \(x = 8\) into the given equation:
\[y = \frac{3}{2}(8) - 3\]
Now, we calculate the product of \(\frac{3}{2}\) and \(8\). Dividing \(8\) by \(2\) gives \(4\), and multiplying \(4\) by \(3\) results in \(12\):
\[y = 12 - 3\]
Finally, subtracting \(3\) from \(12\) gives us the result:
\[y = 9\]
Thus, when \(x = 8\), the value of \(y\) is \(9\).
Linear functions are used in many everyday situations, such as calculating the cost of a service that has a fixed fee and an hourly rate. Suppose a repair person charges a base fee of \(\$3\) and an additional rate of \(\$1.50\) per hour of work. The cost \(y\) after \(x\) hours is given by the function \(y = 1.5x - 3\). If the repair person works for \(8\) hours, the total cost would be \(y = \frac{3}{2}(8) - 3 = \boxed{9}\) dollars. This model helps businesses and customers predict costs accurately.