Question 1125527
the equation is 65 * t + 100

t is the number of hours since 8:00 am.
d is her distance from home.


at 12:00 noon, she has been on the road for 4 hours (12 - 8 = 4).


d = 65 * t + 100 becomes d = 65 * 4 + 100 which becomes d = 260 + 100 which results in d = 360 miles from home.


the d-intercept would be the value of d when t = 0.


when t = 0, the equation becomes d = 65 * 0 + 100 which results in d = 100.


in context of this problem, i believe this means she was already 100 miles from home when she started at 8:00 am.


this might be easier to see if you let y = d and you let x = t.


the equation then becomes y = 65 * x + 100.


the d-intercept now becomes the y-intercept, which is the value of y when x = 0.


you can graph the equation of d = 65t + 100 by replacing d with y and t with x.


the graph looks like this.


<img src = "http://theo.x10hosting.com/2018/100805.jpg" alt="$$$" >


the blue line is the graph of the equation.


the orange lines are there to show the intersection points of the equation when x = 0 and x = 4.