Question

haley pays a monthly fee of $20 for her cell phone and then pays 5 cents per minute used. the total cost of haleys monthly cell phone bill can be expressed by the function ( c(m)=0.05m + 20 ), where ( m ) is the number of minutes used. what are the domain and range of the function ( c(m) )?

Explanation:

Step1: Analyze the domain

The number of minutes \(m\) used cannot be negative. So, \(m\geq0\).

Step2: Analyze the range

When \(m = 0\), \(C(0)=0.05\times0 + 20=20\). As \(m\) increases (since \(m\geq0\) and the coefficient of \(m\) is positive), \(C(m)\) also increases. So, \(C\geq20\).

Answer:

domain: \(m\geq0\), range: \(C\geq20\)