To find the equation for the line, you need to look at the two points' coordinates and the differences between the x and y values. I will call the left point A and the right one B. The coordinates of A and B are (1,-3) and (5,-5).
Now, to form the equation, we look at the type of like/curve. It is a straight line, so the equation will be a linear equation in the form y = ax + b, where a represents the slope and B represents the y-intercept. To find the slope, take the two points A and B, and do the calculation dy/dx i.e. difference in y over difference in x. The difference in y is -5 --3 = -5 + 3 = -2. The difference in x is 5 - 1 = 4.
Now, do the calculation.
-2/4 = -0.5
Now, find the y-intercept. It is -2.5.
Finally, the equation in slope-intercept form (ax + b) is this:
-0.5x + -2.5
Simplify:
-0.5x + -2.5 = -0.5x - 2.5
To further simplify, you can factorise it, but that is optional: -(0.5x + 2.5)
Answer: -0.5x - 2.5