Part A: In order to make an equation without a solution, all you need to do is this:


This makes the equation impossible, as no number equals itself plus two.
Part B: This is easier. Literally every random equation should work.


Now, use substitution:

x = 2
Answer:
x=10.5
Step-by-step explanation:
5(x+3)=(6)(12)-[.5(6)(12-x)]
5x+15=72-36+3x
reduce
2x=21
x=10.5
check
5(10.5+3)=(6)(12)-[.5(6)(12-10.5)]
52.5+3=72-4.5
reduce
67.5=67.5
Answer:
3 hours
Step-by-step explanation:
Because first 3 friends have water that last 6 hours when you double the amount of people you get less water, I don't speak good English to explain but you have to subtract 3 from 6 because 3 is amount of people that need water that lasts 6 hours and when you have more people you get less water sooooo you subtract 3 from 6.
Hope you understand!