Write an equation of the line below.

The first thing you have to find is the y-intercept.

The y-intercept is when the line INTERCEPT the y-axis and as you can see point 4 is the one that is intercepting.

To find the slope you just have to use the slope intercept form
M= rise/run

rise(up+/down-) and run(right+/left-)

So you put your pencil in point for and go 2 times up(+) and then 6 times left(-) to each the other point.

You slope is -2/6 or you can simplify to -1/3 because you can divide by 2 (2:2=1 and 6:2=3)

The slope was negative because number 2 is positive and number 6 is negative (+) + (-) is negative.

The final equation is y= -1/3x+4

The formula that you use is this y=Mx+b

(M is the slope, x is just x and b is the y intercept)

Hope this explanation helps you :D