Answer : The substances half life in days is, 5.6 days.
Step-by-step explanation :
Half life : It is defined as the amount of time taken by a radioactive material to decay to half of its original value.
All radioactive decays follow first order kinetics.
The relation between the half-life and rate constant is:

where,
k = rate constant = 0.1235 per days
= half-life
Now put all the given values in the above formula, we get:


Thus, the substances half life in days is, 5.6 days.
Answer:
rational
Step-by-step explanation:
Step-by-step explanation:
This is what it is equal to:
9×3x=27x
9×8=72
Therefore it will be:

hope it helps!
Answer:
6
Step-by-step explanation:
→ Set up an equation
125 + 15x = 215
→ Minus 125 from both sides
15x = 80
→ Divide both sides by 15
x = 6
Answer:
Step-by-step explanation:
We group the number 5:
5(x² + 3x + 2.25)
Now inside the brackets we'll take the square root of the coefficient of the x and the square root of the last number, then remove the square from the x and write it as a sum:
5(x+1.5)²
What's the idea behind this?
Well, remember that when you have something in the form:
(a+b)²
It actually means:
a² + 2ab + b²
In our case a was x, and b was 2.25. For bringing it into the shorter form we have to take the square root of a and b.
Sorry if you don't understand. Tell me if you need help to get the xoncept better.