If you add a positive and a negative, you end up subtracting. If your sum is lower than any of the numbers you are adding together, then there is a negative. In this case, your only negative number is -8, but if there were others, you could find this equation by doing negative six minus two (because the equation was originally addition, it would still be subtraction to check your work or find the answer in this case.)
The band is selling boxes of fruit to raise money for new uniforms. Boxes of oranges cost $12 per box and boxes of grapefruits cost $15 per box. To get free shipping on all of the fruit each band member must sell at least 25 boxes of fruit. In order to meet your goal, you want to sell at least $500 worth of fruit.