7/10n + 14 = 49
7/10n = 35
n = 35 x 10/7
n = 50
Answer:
3x+75=180
3x=180-75
3x=105
x=105/3
x=35
10 , 20 , 30 , 40 , 50
8, 16 , 24, 32, 40
40 minutes
3x + 4y = 16 Write original equation
3x + 4y - 4y = -4y + 16 Subtract 4y from each side
3x = -4y +16 Simplify
3x/3 = -4y/3 + 16/3 Divide each side by three
x = -4y/3 +16/3 Simplify
I hope this helps!
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.