Y = mx + b
m is your slope AKA rate of change
b is the y intercept.
from the graph we can see that the y intercept (b) is 15. (look at the y axis and see what point the line crosses on the y, here it is 15, in-between 10 and 20)
slope is rate of change. to figure this out remember slope = rise over run:

so pick two points. how much does one point rise after the other point you picked? In the graph it rises 1 square so rise = 1
Now looking at the same two points, how far away from each other are they on the x axis? Looking at the graph they are 2 squares away from each other. so run = 2
Now plug these numbers into the rise over run formula:

Now we have everything we need to put into our formula for a line:


For number 16 you should get:

after you do the same steps again yourself
Slope = -4/5
to calculate the slope m use the gradient form
m = y2 -y1
————
x2 - x1
let (x1, y1) = (3,1) and (x2, y2) = (-2, 5)
m = 5 - 1 4
———- = ——-
-2 - 3 -5
= - 4/5
It’s the 31 hope this helps you