find the slope and y intercept of line. (-11.6,15.8) and (-10/8,12.8)
Those are not the line; they are the coordinates of two points ON the line, (x1,y1) and (x2,y2).
The slope is m = (y2 -y1)/(x2-x1)
Use either point to calculate b in the standard equation format
y = mx + b
I have a suspicion that the 10/8 you have written is supposed to be 10.8.
Did you hit the wrong key?