can someone explain this please

A candy store manager wants to know the demand for a candy bar as a function of the price. The daily sales for different prices of the product are shown in the table. Price, x Demand, y $1.00 $1.20 $1.50 N (a) Find the least squares regression line y = ax + b for the data by solving the system for a and b. (Round your slope and intercept to two decimal places.) 3.006 + 3.70a = 104.00 3.706 + 4.69a = 124.90 Y = (b) Use the regression feature of a graphing utility to confirm the result in part (a). (Round your slope and intercept to two decimal places.) H X (c) Use the graphing utility to plot the data and graph the linear model from part (a) in the same viewing window. 100 100 80 8 8