Y=-.5x+3 Explanation: Move the x to the other side by subtracting it from both sides, you end up with 10y=30-5x then you divide 10 from both sides and you end up with y=-.5x+3
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 .