Of course, this statement is FALSE.
Let`s assume that a small town in Nevada had a population of 1,000.
When it lost 20% of its population:
1,000 * ( 1 - 0.2 ) = 1,000 - 0.8 = 800
After that the same town gained 20 % more people:
800 * ( 1 + 0.2 ) = 800 * 1.2 = 960
960 ≠ 1,000
In the end the town`s population was not the same as it was before the downturm.
Inverse function: you need to exchange the position of x and y, in other words,
x = (5-2y^2)/(3y+10) , then, if you need a representation of y with respect to x, then you need to perform some math.

seperable differential equations will have the form

what you do from here is isolate all the y terms on one side and all the X terms on the other

just divided G(y) to both sides and multiply dx to both sides
then integrate both sides

once you integrate, you will have a constant. use the initial value condition to solve for the constant, then try to isolate x or y if the question asks for it
In your problem,

so all you need to integrate is
987164 is in the ones place
3 is in the tens
0 is in the hundreds
2 is in the thousands