(define (P a b c d e f g h i) (lambda (p) (let ((x (car p)) (y (cdr p))) (let* ((D (/ (+ (* a x) (* b y) c)))) (cons (* D (+ (* d x) (* e y) f)) (* D (+ (* g x) (* h y) i))))))) (define e (P 2 4 3/4 -2 3 6 1 3 -5))We conclude that a 2D projection transforms algebraic curves of orders 3, 4 and 5 into curves of the same order.