Final answer:
To represent Zach's federal income tax as a function of hours worked, assume an hourly wage W and use the function f(x) = 0.10Wx, where 0.10 represents the 10% tax rate.
Step-by-step explanation:
To write a linear function representing Zach's federal income tax in terms of the hours he works, we first need to know Zach's hourly wage and then apply the tax rate to his total earnings. However, these details are not provided, so let's assume Zach earns $W per hour. If Zach works x hours, his total income is $W imes x. Since Zach pays 10% in federal income tax, the amount of federal income tax f(x) he pays is:
f(x) = 0.10 imes (W imes x)
Therefore, the linear function is f(x) = 0.10Wx, where W is Zach's hourly wage and x is the number of hours he works.