Hello, Kaylyn,
We'll assume a straight line, which takes the form y = mx + b, where x is the slope and b is the y intercept (the value of y when x = 0). We can calculate m, the slope, by recognizing that slope is the rate of change of y as x is increased. The increase in y (the "rise") divided by the increase in x (the "run") between those two points will give us the "rise/run", which is the slope, m.
Change in x: (8 - (-4)) = 12 (the run) Change in y: (1 - (-2)) = 3 (the rise). The rise/run is 3/12, or 1/4. The slope is 1/4.
y = (1/4)x + b
We can calculate b by using one of the points provided (I'll choose (8,1)) and solve the equation for b:
1 = (1/4)*8 + b
b = -1
So we have y = (1/4)x - 1
Bob
