1/2(2+a)=3a+4/3
first, you use the distributive property
then your problem changes to...
1 + 1/2a = 3a + 4/3
then you subtract 1/2a with 3a
1 = 2 1/2a +4/3
now you subtract 1 with 4/3
-1/3 = 2 1/2a
now you divide -1/3 with 2 1/2a
-2/15 = a
A = -2/15 is your answer. Hope this helps :)