The expression for (r-s)(x) is found by subtracting s from r. That difference is [tex]3 x^{2} -2x[/tex]. The expression for (r+s)(x) is found by adding them, which is [tex]3 x^{2} +2x[/tex]. Now we are told to evaluate (r*s)(x) which means they want us to multiply those and state the "new" expression that results. [tex](3 x^{2} )(2x)=6x^3[/tex]. There you go!
