Answer: 
Step-by-step explanation:
Having the following equation given in the exercise:

You can solve for "a" following this procedure:
1. You can apply the Subtraction property of equality and subtract
from both sides of the equation:

2. Now you must subtract the terms on the left side of the equation. Notice that the Least Common Denominator is "d". Then:

3. Finally, you can apply the Multiplication property of equality and multiply both sides of the equation by "b". So, you get:
