Answer:
Step-by-step explanation:
-8x^2 - 12 + 7x^2 - 9x + 3
-x^2 - 9x - 9
You can always add or subtract
same value to/from both sides of equation. The same is true about multiplication and division.
In your case you have to subtract
x from both sides of equation in order to get rid of it on the left side:


But it's easier to remember that if you want to move some member of equation to other side, you just have to
change it's sign. Let's practice a bit using your equation (I have added "plus" signs where they are usually omitted to better understend what's going on):

Move
2y to the right side:

Move
8 to the left side:

Move both
x and
2y to the right side:
Answer:
The population in 8 years will be of 7313.
Step-by-step explanation:
Population of a town:
The population of a town, after t years, with a doubling time of n years, is given by:

The initial population of a town is 4200, and it grows with a doubling time of 10 years.
This means that 
So

What will the population be in 8 years?
This is P(8). So

The population in 8 years will be of 7313.
Half a million was lost to internet thievery.