Using the formula y=mx+b you can plug in the slope -1/2 giving you y=-1/2x+b now you have to find the y intercept which is the number you get when x=0. Given the points (-2,-6) x being -2 and y being -6 you can find the y intercept by simply substitute these values into the formula giving you (-6)=-1/2(-2)+b. -1/2(-2) is equal to 1 and -6-1 is equal to -7 so that makes the y intercept equal to -7. Your final equation would be y=-1/2x-7