The slope is 2 since each time x increases by 1, y increases by 2. Or put another way, each time we go up 2 units, we move to the right 1 unit. So that's why 2 goes in the box on the left. You can use the slope formula m = (y2-y1)/(x2-x1) to get the same result
The line goes through 4 on the y axis, so this is the y intercept and the value you type into the second box (box on the right).
Recall that y = mx+b is the general slope intercept form m = slope = 2 = 2/1 b = y intercept = 4 The equation y = mx+b turns into y = 2x+4. This is known as a linear equation as it produces a straight line graph.
