A small grocer finds that the monthly sales y (in $) can be approximated as a function of the amount spent advertising on the radio
(in $) and the amount spent advertising in the newspaper (in $) according to
The table gives the amounts spent in advertising and the corresponding monthly sales for 3 months.
a) Use the data to write a system of linear equations to solve for a, b, and c.
b) Use a graphing utility to find the reduced row-echelon form of the augmented matrix.
c) Write the model
d) Predict the monthly sales if the grocer spends $250 advertising on the radio and $500 advertising in the newspaper for a given month.