Answer:
y = -x +9
Explanation:
The equation will be written in slope-intercept form, y=mx+b
Looking at the graph, we can already see that the y-intercept is +9 since that is the point on the y-axis from where the line comes from.
Now, you have to find the slope. Normally, you would pick two points and subtract the y value of the second point and the y value of the first point and put the sum over the difference of the x value of the second point and the first point, y2 - y1/ x2 - x1.
You could have done this or looked at the graph to see that the line has a constant downward slope of -1, go down one and to the right one from (0,9) t ok end up at (1,8).
All that's left to do now is to plug the values of the slope and y-intercept in to give us the equation y = -x +9.