Answer:
y = -1/2x +(4 1/2)
Explanation:
The two marked points (-1, 5) and (1, 4) differ in y-value by -1 and x-value by +2, so the slope is -1/2.
The y-intercept is halfway between the marked y-values, so is at 4 1/2.
Putting these numbers into the slope-intercept form of the equation for a line, ...
... y = mx + b . . . . for slope m and y-intercept b
we have ...
... y = -1/2x +(4 1/2)