Answer:
The equation of the line is y = -x + 9.
Step-by-step explanation:
First, you have to find the gradient by choosing any 2 coordinates that lies on the line. I will choose (0,9) and (9,0). Then you have to substitute it the the formula.
[tex]m = \frac{y2 - y1}{x2 - x1} [/tex]
[tex]let \: (x1,y1) \: be \: (9,0) \\ let \: (x2,y2) \: be \: (0,9)[/tex]
[tex]m = \frac{9 - 0}{0 - 9} [/tex]
[tex]m = \frac{9}{ - 9} [/tex]
[tex]m = - 1[/tex]
Next, you have to put into the slope-form equation, y = mx + c where m represents gradient which is -1 and c is y-intercept. In order to find c in a faster way, you can look at the graph to see which coordinates touches y-axis. So the value of c is 9 :
[tex]y = - x + 9[/tex]
