Question

Diane knows a phone call to a friend costs $1 for the 50 minutes and $1.50 cents for 100 minute. Identify the variables in this situation: x= ____________ y= _______________ M = ____________ b = _______________

Answer 1

Explanation:

Let y represent the cost of the call.

Let x represent the number of minutes.

The equation of a straight line can be represented in the slope-intercept form, y = mx + b

Where b = intercept

Slope, m =change in value of y on the vertical axis / change in value of x on the horizontal axis

change in the value of y = y2 - y1

Change in value of x = x2 -x1

y2 = 1.5

y1 = 1

x2 = 100

x1 = 50

Slope = (1.5 - 1)/(100 - 50) = 0.5/50 = 0.01

To determine the intercept, we would substitute x = 50, y =1 and m= 3 into y = mx + b. It becomes

1 = 0.01 × 50 + b = 0.5 + b

b = 1 - 0.5 = 0.5

The equation becomes

y = 0.01x + 0.5