For the first equation the solution for 'A'
- Move all terms that don't contain a to the right side and solve. a = −3 + 3c/2
And the solution for 'C' (It's still the same equation..)
- Move all terms that don't contain c to the right side and solve. c = 2 + 2a/3
Then as for the second one, the solution for 'A'
- Subtract 2c from both sides of the equation. a = 11 − 2c
As for the 'C' is..
- Move all terms that don't contain c to the right side and solve. c = 11/2 − a/2
____
I hope this helps, as always. I wish you the best of luck and have a nice day, friend..