Answer:

Step-by-step explanation:
make one side equal to zero:

find two factors that multiply to -36 and add to -5 (-9 & 4)

factorise


solve for x

I think the answer is sometimes or never.
3/10 is 0.3 im finding more to answer...
The 20th costumer will get both.
You have to fine the least common multiple of both numbers. So the closest those two numbers have is 20.