Answer:
Slope = Rise/Run
To graph, you first need the y-intercept.
In y = -1 + 2x, the y-intercept is -1. Start in -1 and then go two units up, and 1 unit to the right which will represent the slops, 2.
In y = -4 + 2x, the y-intercept is -4, so you'll start at -4, then go 2 u its up, and 1 to the right which will represent the slope, 2.
To find y-intercept:
y = mx + b | main things: m = slope b = y-intercept
Hope it helps!