Calcular la suma entre los polinomios que se listan a continuación:

1.) $a-2b-3c;-3a+b+2c;2a-3b+c$
2.) $3a+2b-c$;$-a+3b+2c;$$2a-b+3c$
3.)$-3x+2y+z;\, x-3y+2z;$$2x+y-3z$
4.)$-x+2y+3z;3x-y+2z;2x+3y-z$
5.)$4a+3b+5c;-2a+3b-8c;a-b+c$
6.)$-15a-19b-18c;14a+15b+8c;a+5b+9c$
7.)$25a-15b+c;13a-10b+4c;a+20b-c$
8.)$-16a-10b+5c;10a+5b+c;6a+5b-c$
9.)$5ax-7by+cz;ax+2by-cz;-3ax+2by+3cz$
10.)$20p+q-r;\, p-20q+r;\, p+q-20r$
11.)$-5ab+6bc-7ca;\, ab-bc+ca;$$8ab-4bc+3ca;-2ab-2bc+4ca$
12.)$15ab-27bc-6ca;\,14ab-18bc+10ca;$$-49ab+45bc-3ca$
13.)$5ab+bc-3ca;\, ab-bc+ca;$$-ab+bc+2ca$
14.)$pq+qr-rp;-pq+pr+rp;\, pq-qr+rp$
15.)$x+y+z;2x+3y-2z;3x-4y+z$
16.)$2a-3b+c;$$15a-21b-8c;3a+24b+7c$
17.)$4xy-9yz+2zx;-25xy+24yz-zx;\,23xy-15yz+zx$
18.)$17ab-13bc+8ca;-5ab+9bc-7ca;2ab-7bc+ca$
19.)$47x-63y+z;-25x+15y-3z;-22x+48y+15z$
20.)$23a-17b-2c;-9a+15b+7c;-13a+3b-4c$