Помгите решить 2m+3n+3(5n+7m)

Question

Помгите решить 2m+3n+3(5n+7m)

Answer 1

2m+3n+15n+21m=23m+18n

Answer 2

1) 3*5n = 15 n ; 3*7m = 21m
2) 2m + 3n + 15n + 21m = 23m + 18 n
3) 2m + 21m = 23 m
4) 15n + 3n = 18 n