Question

can someone explain this I dont understand it

Answer 1

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:

$slope = \frac{rise}{run}$

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:

$slope \: = \frac{1}{2}$

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

$y = mx + b$
$y = \frac{1}{2} x + 18$

For number 16 you should get:

$y = \frac{1}{5} x + 3$

after you do the same steps again yourself