Answer:
A) y = 0.3x+24
B) 283.5 dollars
Explanation:
A) To create an equation in slope-intercept form, we can start by using the numbers the problem gave us and represent them as coordinates. Generally, time is always our x-value.
(230,93)
(530,183)
Now that we have our two coordinates, we can plug them into the slope-intercept formula: y₂-y₁/x₂-x₁ to find our slope.
(183-93)/(530-230) = 0.3
Now that we have our slope, we can plug it into our equation.
y = 0.3x + b
To find our y-intercept, we can take either one of our 2 coordinates (x,y) and plug them into the equation to solve for b.
93 = 0.3(230) + b
93 = 69 + b
93 - 69 = b
b = 24
Now that we have found our y-intercept, we can plug it into b to complete the equation.
y = 0.3x +24
B) If 865 minutes are used, we can plug 865 into x in our equation to find the total cost.
0.3(865) + 24 = 283.5