Perpendicular is opposite and reciprocol of the slope. Your slope is -2 so the opposite of that is positive 2, and the reciprocol is 1/2. When you graph that you should have a point at (8,2). y=1/2x -2
If you saving grows every year, then your saving is times your saving from last year. Therefore, after one year, you will have , then after years, you will have , then after years, you will have .