Answer:
a =
Explanation:
To isolate the a, the first thing I would do is bring the d to the other side of the equation, remember to switch the sign. This would give me a(b+c) = e+d. Next, in order to get rid of the (b+c), bring it to the other side by dividing since it is attached to the a variable by multiplication. This leaves me with a = e+d / b+c. Make sure not to distribute, this would duplicate your a variable.