;; I got the same idea as hi-artem to use map procedure, however I think we need to use the generic negate for coeff as well
(define(negate-poly p)(make-polynomial (variable p)(map(lambda(term)(make-term
(order term)(negate (coeff term))))(term-list p))))

hi-artem

`(define (negate-terms termlist) (map (lambda (t)(make-term(order t) (- (coeff t)))) termlist))`

CrazyAlvaro