The current depth of the hole is at least 20 feet below ground level.
Inequality is an expression that shows the non equal comparison of numbers and variables.
Let d represent the current depth of the hole.
To be at least 40 feet below ground level, he need more than 2 times its current depth.
2d < -40
d < -20
Hence the current depth of the hole is at least 20 feet below ground level.
Find out more on inequalities at: brainly.com/question/11613554
Answer:
Option B.
all real numbers
Step-by-step explanation:
We have
and 
They ask us to find
(fog)(x) and it's Domain
To solve this problem we must introduce the function g(x) within the function f(x)
That is, we must do f(g(x)).
So, we have:


Then:

The domain of the function f(g(x)) is the range of the function
.
Since the domain and range of g(x) are all real numbers then the domain of f(g(x)) are all real numbers
Therefore the correct answer is the option b: 
And his domain is all real.
Answer:
a. closed under addition and multiplication
b. not closed under addition but closed under multiplication.
c. not closed under addition and multiplication
d. closed under addition and multiplication
e. not closed under addition but closed under multiplication
Step-by-step explanation:
a.
Let A be a set of all integers divisible by 5.
Let
∈A such that 
Find 

So,
is divisible by 5.

So,
is divisible by 5.
Therefore, A is closed under addition and multiplication.
b.
Let A = { 2n +1 | n ∈ Z}
Let
∈A such that
where m, n ∈ Z.
Find 

So,
∉ A

So,
∈ A
Therefore, A is not closed under addition but A is closed under multiplication.
c.

Let
but
∉A
Also,
∉A
Therefore, A is not closed under addition and multiplication.
d.
Let A = { 17n: n∈Z}
Let
∈ A such that 
Find x + y and xy


So,
∈ A
Therefore, A is closed under addition and multiplication.
e.
Let A be the set of nonzero real numbers.
Let
∈ A such that 
Find x + y

So,
∈ A
Also, if x and y are two nonzero real numbers then xy is also a non-zero real number.
Therefore, A is not closed under addition but A is closed under multiplication.
Answer:
7
Step-by-step explanation:
7 x 4 = 28 - 5 = 23
7 + 16 = 23