First distribute in the 2 on the left side to get 6d+6=7+6d
Then, you would combine the variables to be on one side of the equation by doing -6d. However, this would cancel out the d by leaving you with 0d+6=7. That is the same thing as saying 6=7.
The answer to this equation is no solution because 6 is NOT equal to 7.
0/3 is the same thing as 0, so write those nxt to each other. Then 1/3, 2/3. Lastly 3/3 is the same as 1, so write those nxt to each other.
(3/500)*(12,000) = 72 batteries . . . answer is B) 72