Hello there. There are two ways to solve this question.
We can plug in the values of the points that the line in red passes through the graph in those equations and see which of them are the one that best describes the graph
or
We can find the equation of this line and the answer right away.
For example, you can see the points (0, 1) and (2, 0) on this graph, considering all the squares have a length of 1, it is, the graph is uniformly spaced.
The equation of a line that passes through two points (x0, y0) and (x1, y1) is given by: y - y0 = m * (x - x0), in which m is the slope of the line.
The slope can be found using the formula: m = (y1 - y0)/(x1 - x0)
Plugging in the coordinates of the points we found, we'll get:
m = (0 - 1)/(2 - 0) = -1/2
Now, plugging in the coordinates and the value of the slope into the equation, we'll get:
y - 0 = -1/2(x - 2)
y = -x/2 + 1
Multiply both sides of the equation by a factor of 2
2y = -x + 2
Add x on both sides of the equation
x + 2y = 2
This is the equation of this line and is the answer contained in the first option.