First one simplifies to 2x + 6 = 2x + 7 which can't be true so this one has No Solution.
Same applies to the second equation ( 5x + 15 = 5x - 15) No solution
also the last one has no solution because it simplifies to 4x + 20 = 4x + 19
You can use the factors of the volumes 24, 27 and 48:
For example:
8 by 3 by 1 is a total volume of 24
or if you know that 4 times 2 is 8:
4 by 2 by 2
and so on
30 - 18 = 12
So he has 12 miles left for this week.
There are 3 more days
So 12 divided by 3
Which is 4, so he needs 3 more hours per day for the remaining 3 days
-16w-26+9w=-61
-16w+9w=-61+26
-7w=-35
w=5
The remaining area is 20% of the previous area.
Hope this Helps!