Exercise 2.93: Modify the rational-arithmetic
package to use generic operations, but change make-rat so that it does
not attempt to reduce fractions to lowest terms.  Test your system by calling
make-rational on two polynomials to produce a rational function:


(define p1 (make-polynomial 'x '((2 1) (0 1))))
(define p2 (make-polynomial 'x '((3 1) (0 1))))
(define rf (make-rational p2 p1))

Now add rf to itself, using add. You will observe that this
addition procedure does not reduce fractions to lowest terms.