3d + 8 = 2d - 7 equals d = -15.
First, subtract 2d from both sides. Your problem should look like: 3d + 8 - 2d = -7.
Second, simplify 3d + 8 - 2d to get d + 8. Your problem should look like: d + 8 = -7.
Third, subtract 8 from both sides. Your problem should look like: d = -7 - 8.
Fourth, simplify -7 - 8 to get -15. Your problem should look like: d = -15, which is your answer.
Hopefully this helps, I'm not exactly sure what you meant by "is equations," but this is how you solve the problem.

Step-by-step explanation:
The amount of time from 10pm to 7am is 9 hours. However, the time indicated is 7:10am. Since there are 60 minutes in an hour, 10 min is equal to 1/6 of an hour. Therefore, the total time that the water level of the pool decreased is
hours or
hours. To find the rate at which the water level decreased, we divide the change in the water (in inches) by the time it took to reach that level. So we write
rate of change 



Answer:
378 pictures
Step-by-step explanation:
600 multiplied .63
Answer:
2
Step-by-step explanation: 2+5=7