Hi there!

First we rearrange the sum in order to add both of the fractions first. We can rearrange because the only thing we need to do is adding.

Add the fractions.
** If you don't get this, think of this story: you lack 1/3 of an apple pie and someone gives you 2/3 of pie. How much pie do you have left?
- 1 / 3 + 2 / 3 = 1 / 3 **

Finally add 4 to our found fraction.

Therefore, the answer is 4 1/3.
Answer:
20x - 6
Step-by-step explanation:
You just multiply 2 by 10x and by -3
Answer:
6400
Step-by-step explanation:
so every 5 hours it gains 800 bacteria so 4800+800=5600 (hour 10)
and 5600+800=6400 (hour 15)