Follow the formula: (y2 - y1) / (x2 - x1). So 4-(-4) and 2-(-2). A negative and a negative equal a positive so 8/4. Then simplify. Which gives you 2/1. Hope this helps.
In 5 years, the price increased about 30%. I am not good at perentages, so correct me if I'm wrong. Also this is an estimation, not the exact percentage.
