Answer:
-3
a = 6/7
Explanation:
The answer is -3 because:
1) First, we have to isolate a
2) In order to isolate a, we have to -9 from 15 and +9
New equation: 7a = 6
3) We know that 6 + 9 equals to 15
4) In order to get 6 as a, we know that a has to equal a fraction
5) Then, we know that 7 x 6 equals 42 and 42/7 is equal to 6
6) Therefore, a is equal to 6/7
7) Now, 7 times 6 is 42. Then, 42 divided by 7 is 6.
8) Finally, 6 - 9 equals -3
Hope this helps!