Answer:
3
Step-by-step explanation:
2x + 3 = -x + 12
subtract 3 from both sides
2x = - x + 9
add x to both sides
3x = 9
divide by 3
x = 3
It is the first option i think

For each time period, each time "t" increases by one, the population will be multiplied by 4.
576 I hope this help cause I did this two years ago so I'm a little rusty but I think this is correct