subring of $ [R ] = ( Pol[R ], Q, @ ). ( Consider the set CPR introduced in Homework Problem 3 of Investigation 19 . ) Problem 8. Suppose R = ( R, +, * ) and S = ( 5, 1, * ) are rings and suppose that I is an ideal of R and \\\\ is an ideal of . Show that I X ) is an ideal of the product ring R XS