An equation that is true for all values of the variables in its domain is <u>an identity</u>
<u></u>
Hope that helps!
Answer: 
Step-by-step explanation:
Given the equation
you need to solve for the variable "b".
You need to apply Distributive property on both sides of the equation:

Now you need to add 21 to both sides of the equation:

Subtract
from both sides:

And finally, you can divide both sides of the equation by 18:

Answer:

Step-by-step explanation:
One formula for the reproduction of bacteria is

Data:
N = 2
N₀ = 1
t = 15 min
Calculation:

Answer:
The annual haircut in the United States contains $ 20,000 from zinc
Step-by-step explanation:
1 kg of hair contains ___________________ 0.0002 kg of zinc
25,000,000 kg of hair _________________ X

It means that 25,000,000 kg of hair contains 5000 kg of zinc.
Otherwise,
If 1 kg of zinc _____________ worths $4
5,000 kg of zinc___________ X

X= $20,000