Notes:
The notation ">=" without quotes means "greater than or equal to"
The upper case "U" means "set union"
Instead of using the intersection symbol, I will use a lower case 'n'
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Problem 1
A = {x | x < 1} which is the set of x values smaller than 1
B = {x | x >= 5} is the set of x values that are equal to 5 or larger
A U B = set of values that are from set A OR they are from set B (or both)
A U B = {x | x < 1 or x >= 5}
we simply connect the two inequalities mentioned with an "or"
note: how there is no overlap between the two regions. The "U" means "set union" which is like a sort of glue to tie the two sets together with an "or".
Answer: {x| x < 1 or x >= 5}
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Problem 2
A = {x | x < 1}
C = {x | x = 5} which is the set of one value only: 5 (x cannot equal any other value)
A U C = {x| x < 1 or x = 5}
So if a number is in set A U C, then this number is either less than 1, OR it is equal to 5
Answer: {x|x < 1 or x = 5}
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Problem 3
B U C = {x | x >= 5} because set C already has the "or equal to" part in there.
Set C is a subset of set B. If an item is in set C, then it is also in set B.
Answer: {x| x >= 5}
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Problem 4
Again recall that I'm using an 'n' to indicate "set intersection" instead of the upside down "U" symbol
A n B is the set of items that are in BOTH sets A and B at the same time. From problem 1, I mentioned there's a gap. There is no x value that is both less than 1 AND greater than or equal to 5. So this means that
A n B = empty set
which we use the "O" with a slash through it. This is a special symbol to indicate "empty set"
Another way to write "empty set" is to use curly braces with nothing inside like so { }
Answer: The "O" with a slash through it
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Problem 5
B n C is the same as {x| x = 5}
Why? Because if an item is in B n C, then it has to be in BOTH set B and set C at the same time. The only way this happens is if x = 5. If x is any other value, then it won't be in set C
Answer: {x| x = 5}
Answer:
Graph a
Step-by-step explanation:
Step-by-step explanation:
a = m - n
or
m = a + n
or
n = m - a
Step-by-step explanation:
20.
In each proof, start by looking at what you're trying to prove. We want to prove that two triangles are congruent. To do that we use one of the following: SSS, SAS, ASA, or AAS.
To decide which one to use, look at the information given. We're given two pairs of congruent sides, so we can narrow the strategy down to either SSS or SAS. We aren't told anything about the third pair of sides, but we <em>can</em> see that ∠JNK and ∠MNL are vertical angles. We'll use this to show the triangles are congruent by SAS.
1. JN ≅ MN, Given
2. ∠JNK ≅ ∠MNL, Vertical angles
3. NK ≅ NL, Given
4. ΔJNK ≅ ΔMNL, SAS
21.
Repeat the same steps as 20. Again, we're trying to prove two triangles are congruent, so we have 4 strategies to choose from. Just like before, we're given two pairs of congruent sides, so we'll use either SSS or SAS. And again, we aren't told anything about the third pair of sides, but we can see that both triangles are right triangles. So we'll use SAS again.
1. MN ≅ PQ, Given
2. ∠LMN ≅ ∠NQP, Right angles are congruent
3. LM ≅ NQ, Given
4. ΔNML ≅ ΔPQN, SAS
