Need method of least squares solution for below problem. From Chapter 10.5 (Causal Forecasting with Linear Regression) of Introduction to Management Science: A Modeling and Case Studies Approach with Spreadsheets (Fredrick Hillier, 6th Edition.). Please do not respond just to say you cannot solve this, which delays others from answering. Many thanks.

Sales over the past 10 years are shown below. Using the method of least squares, calculate the values of a and b to complete this regression equation. What is your forecast for next year's sales? Year 1 2 3 4 5 6 7 8 Sales 1,020 1,980 1,910 1,640 1,590 1,930 1,090 1,960 1,920 1,160 9 10 (Do not round intermediate calculations and round your answer to 3 decimal places.) Sales (1.333) (Do not round intermediate calculations and round your answer to 2 decimal places.) Sales