If I have two equations how do I combine them?

Do I have to write something like this or is there a shorter way? Maybe something like `solve(eq1,eq2,a)`

?

```
using Symbolics
@vars a b c
eq1 = ( a = b + c)
eq2 = ( b = 3c - a)
substitute(eq1,eq2.lhs => eq2.rhs)
```