This could be rephrased as:
You start with 100 grams of a substance. One year later you have 70 grams. What is the half-life?
We need this formula:
half-life = (time * natural log (2)) / natural log (beginning amount / ending amt)
half-life = (1 year * .69315) / natural log (100 / 70)
half-life = (.69315) / 0.35667494396
half-life = 1.9433661145 years
Rounding to nearest year half-life = 2 years
Sourse: https://www.1728.org/halflif2.htm
(See problem 3)
Consider posting each question separately, please.
Given <span>-2.8k-4.31=-15.79 :
1) Isolate the "k" term on the left by adding 4.31 to both sides of this equation.
2) Simplify the right side.
3) Divide both sides by -2.8 and you'll have the answer: k = ?</span>
Answer:
20/
9
Step-by-step explanation:
80/
36
=
20/
9
=
2 wholes and 2/
9
The statement is an equation in word form, so to solve, write the statement as an equation. In the phrase "The quotient of a number and 9" let X represent "a number." The statement as an expression is X / 9. "Is the same as" indicates the two expressions are equal, and "the difference of 14 and 8" means 14 - 8.
Put it together and you get the expression X / 9 = 14 - 8. From here, you have to solve for X by simplifying the expression and multiplying both sides by 9.
X / 9 = 14 - 8
X / 9 = 6
9 (X / 9) = (6) 9
X = 36