When ever you combine different elements the chemical properties change because elements are different , unless you combine the exact same elements.
Example: 
We can see that there is more than one number with the variable x, therefore, we say they're ''like terms'' and because of that they can be summed. We do this with all of the other numbers with similar variables. If no numbers with similar variables are left, like 4a, you don't do anything but write them as they are. You can also see that 8 and 9 can also be summed because neither of them has a variable, therefore they're similar.
In this step, you just do the operation with the numbers and keep the same variable.


since there are not more numbers similar in variables, this operation is done.

If the population quadruples every period say hour, that means the "rate of growth" is 300%, so whatever the current amount, increased by 3 times as much is 4 times the current amount, or a quadrupled amount.
Answer:
2x-1
Step-by-step explanation:
Just solve this way.
(2/3)x-(1/3)=(1/3)y.
Now find y in terms of x.
Answer:
25
Step-by-step explanation: