Slope-intercept form:
y = mx + b
"m" is the slope, "b" is the y-intercept (the y value when x = 0) or (0,y)

Rise is the number of units you go up(+) or down(-)
Run is the number of units you go right
If the slope is 3/2, from each point you go up 3 units, and to the right 2 units
If the slope is -2, you go down 2 units, and to the right 1 unit.
To find the solution to the system, you find the intersection point (the point where the lines meet)