Help me please!!HELP MEEEE!!!!решите уравнение(1/7+1/3)•a=1/7

Question

Help me please!!HELP MEEEE!!!!
решите уравнение
(1/7+1/3)•a=1/7

Answer 1

1/7a+1/3a=1/7; 3/21a+7/21a=1/7; 10/21a=1/7; a=1/7*21/10; a=3/10.