Answer:
y=-1.7x+8
Explanation:
An equation of a line is y=mx+c
m is the gradient and c is the y intercept, which is where the line intercepts y.
you work out m getting two points and then subtracting y - y ÷ x - x
So in this graph, if we chose points (6,-2) and (3,3) then we would do this equation.

So m = -1.7
c = 8 because it goes through 8 in y.
So the equation is y=-1.7x+8