How does y=mx + c work?

In the equation y = x + 2. 2 is you're y intercept. this means you want to start at the point (0,2). now is your slope and it is just x, it is basically 1x. and since slope is rise over run and 1x is 1 over 1 up your next point would be (1,3) now if you had something like y = 3x + 2, you would still start at (0,2) since you're y-intercept is +2 (why they call id "c" i have no idea), then since it is 3x it basically 3/1. so you would go up 3, right one, making your new point (1,5). Now let's say x is negative (-x) therefore it would be (-1, 1). So you would go down 1, right one. i hope this helps.