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)? domain: m≥0 range: c≥20

Explanation:

Step1: Determine domain

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

Step2: Determine range

When $m = 0$, $C(0)=0.05\times0 + 20=20$. As $m$ increases (since $m\geq0$), $C(m)$ also increases. So, $C(m)\geq20$.

Answer:

Domain: $m\geq0$; Range: $C(m)\geq20$