Answer:
789
Step-by-step explanation:
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:
Step-by-step explanation: perimeter = side * 4
therefore the answer is 40 *4
160
Like terms are similar in exponents.
12x^2 can be combined with -3x^2
9x^3 with -5x^3
-8x^4 is on its own
Final=
-8x^4 + 4x^3 + 4x^2