slope:
find two places where the line neatly crosses the grid. As example, we can choose : (-2 , -7) and (2 , 1)
slope = rise/run
so:
slope = change in y/change in x
slope = (-7 - 1) / (-2 - 2)
slope = -8/-4
slope = 2
y-intercept:
this is where the blue line crosses the y (vertical) axis. This occurs when x = 0. y -intercept is: (0 , -3).
equation format: y = mx + b
where m = slope and b = y intercept
so:
y = 2x - 3