Infer and compare growth or decay rules using exact common-base values.

Answer: 4

1. Two hours multiply the population by 9
2. each hour multiplies by 3.
3. At hour 0 there are 4 cells.
4. Solve 4×3t=324:t=4.

Answer: 7

1. Over two hours it retains 91​
2. it retains 31​ each hour.
3. Solve 3t13122​=6;
4. since 2187=37,t=7.

Answer: 4

1. Two hours multiply the population by 9
2. each hour multiplies by 3.
3. At hour 0 there are 3 cells.
4. Solve 3×3t=243:t=4.