Hey there :)
Before translating the sentence into mathematics, let r represent 'a number'
5 times a number = 5r
2 times that number = 2r
The difference between them = 5r - 2r
* Your equation
5r - 2r
* Solving the equation
= 5r - 2r
= 3r
Time = Distance / speed
Time = 20 miles / 12mph
Time = 1 and 2/3 hours ( 1 hour and 40 minutes)
In general, the average rate of change of f (x) on the interval a, b is given by f(b) – f(a) / b – a. The average rate of alteration of a function, f (x) on an interval is well-defined to be the variance of the function values at the endpoints of the interim divided by the difference in the x values at the endpoints of the interval. this is also known as the difference quotient that tells how on average, the y values of a function are changing in connection to variations in the x values. A positive or negative rate of change is applicable which match up to an increase or decrease in the y value among the two data points. It is called zero rate of change when a quantity does not change over time.
You have the right idea but the endpoint is at the wrong location. Instead, the green dot should go at -1. The shading is to the right. We use a closed filled in circle here (instead of an open hole) to tell the reader "include the endpoint". So -1 is part of the solution set.
In short, the graph consists of a closed filled in circle at -1 with shading to the right. This visually describes all values that are larger than -1, or equal to -1.
