Answer:
qwertyuo;kjghjkl;'
Step-by-step explanation:
43r567890op0oy76t43rtbhjm,ju765
the area is 180 cm. to find the perimeter you would do 15+15+14+14 to get 54 cm. So for area you do (l×w) which is 15×14=180.
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.
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