Answer:
1) 13a+7b
6a+7a+10b-3b ,gives you 13a+7b
2) 2v+16c
9-7v+10c+16, gives you 2v+16
3) 21s+10r
8s+13s+6+4r, gives you 21s+10r
4) -d+10e
4d-5d, gives you -1, and 6e+4e, gives you 10e
5)11g+16f
7g+4g, gives you 11g, and 13f+3f gives you 16f
6) 21p+6q
9p+12p,gives you 21p, and -13q+19q, gives you 6q
7) 6b+3c
2b+4b, gives you 6b, and 9c-6c, gives you 3c.
8) 26m+9k
14m+12m, gives you 26m, 5k+4k, gives you 9k.
9) 18n+24p
14n+4n, gives you 18n, and 12p+12p, gives you 24p.
10) a+3b
5a-4a, gives you a, and 10b-7b, gives you 3b.