Question

brendas monthly cell phone bill
the linear function graphed shown represents brendas
monthly cell phone bill based on the number of hours she
uses. what is her hourly rate?
$27 per hour
$12 per hour
$15 per hour
$39 per hour

Explanation:

Step1: Recall the slope formula

The slope formula is \(m=\frac{y_2 - y_1}{x_2 - x_1}\), where \((x_1,y_1)\) and \((x_2,y_2)\) are two points on the line.

Step2: Identify two points

We can use the points \((1,27)\) and \((2,39)\). Here \(x_1 = 1,y_1=27,x_2 = 2,y_2 = 39\).

Step3: Calculate the slope

Substitute the values into the slope formula: \(m=\frac{39 - 27}{2 - 1}\).

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Answer:

\(\$12\) per hour