We observe that a line will pass through 3 points, but to find a slope we only need two.
We see that it passes through points (assuming the scale of graph is 1 : 1)
and
.
We can use slope formula that applies for any line and produce the same slope for any two different points on the line
![m=\frac{\Delta{y}}{\Delta{x}}=(y_2-y_1)/(x_2-x_1)=(-1-1)/(2-0)=-1](https://img.qammunity.org/2021/formulas/mathematics/middle-school/78rthlrwbf2ztm49jm8tmvyzu69hjd12hv.png)
So the slope is -1 also it intersects y-axis at
so the general form of the linear function is
![f(x)=mx+n](https://img.qammunity.org/2021/formulas/mathematics/high-school/4kmwu9vks4oqvg74klr1tbhgx6hzviabqv.png)
That is in your case
![\boxed{f(x)=-x+1}](https://img.qammunity.org/2021/formulas/mathematics/middle-school/gfl6qgzqkdnx05s5erwalaep032y0qvwcu.png)
Hope this helps.