Approximate the area under each curve over the specified interval by using the indicated number of subintervals and evaluating the function at the right-hand endpoints of the subintervals.
1. f(x)=9-x^2 from x=1 to x=3; 4 subintervals.
2. f(x)=x^2 +x+ from x= -1 to x=1; 4 subintervals.