The amount of the substance (At) at any time t is calculated through the equation,
At = (A0)(e^-kt)
where A0 is the initial amount and k is constant.
For the half-life,
ln (At / A0) = ln 0.5 = -k(5270 years)
The value of k is 1.3153x10^-4 / year.
Substituting this value to the same equation, where At = 0.25A0
ln 0.25 = -(1.3153 x 10^-4)(t)
The value of t from this equation is 10540 years. The closest value to this is letter A.
Given:
m/n-3(m+n)
m=-10 and n=-2
Solving:
-10/-2-3(-10-2) Since m=-10 and n=-2, we substitute them in for the values since they have an equal relationship.
Now, follow Orders of Operations: PEMDAS
-10/-2-3(-12) Simplify parentheses (P)
There are no Exponents (E)
Multiplication (M) and Division (D) are =, so we do whatever operation comes from the left to right.
-10/-2=5 Division comes first on the left.
therefore:
5-3(-12)
-3(12)=-36, Multiplication is last on the right.
therefore:
5-36
5-36=-31 After M/D, we do Addition and Subtraction, which are also =, so we do them left to right.
Therefore -10/-2-3(-10-2)=-31
Answer:
5 and 12
Step-by-step explanation:
First, set up an equation. Since it says that one number is 7 less than the other, we can use x for the number that is 7 less than the other number, and x+7 to represent the other number. We set the equation equal to 17 because the question says that the sum of two numbers is 17.
x+x+7=17
Then, you solve the equation:
x+x+7=17
2x+7=17
2x=10
x=5.
So, the number that is 7 less than the other number is 5. To find the other number, we would add 7 to 5 because the other number would be 7 more than 5.
7+5=12
The two numbers are 5 and 12.
Answer:to caculate the sides
Step-by-step explanation:
Answer:
b - 60
Step-by-step explanation:
Let the number of books in the library be b.
The number of books in the library minus the 60 checked out is translated into a variable expression as b - 60
