Question

Consider U = {x|x is a real number}. A = {x|x ∈ U and x + 2 > 10} B = {x|x ∈ U and 2x > 10} Which statements are true? 5 ∉ A; 5 ∈ B 6 ∈ A; 6 ∉ B 8 ∉ A; 8 ∈ B 9 ∈ A; 9 ∉ B

Answer 1

x+2 > 10 solves to x > 8 after we subtract 2 from both sides

So set A is the set of real numbers that are larger than 8. The value 8 itself is not in set A. The same can be said about 5 as well.

Set B is the set of values that are larger than 5 since 2x > 10 turns into x > 5 after dividing both sides by 2. The value x = 5 is not in set B since x > 5 would turn into 5 > 5 which is false. The values x = 6, x = 8, and x = 9 are in set B.

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Summarizing everything, we can say...

5 is not in set A. True

5 is in set B. False

6 is in set A. False

6 is not in set B. False

8 is not in set A. True

8 is in set B. True

9 is in set A. True

9 is not in set B. False

Answer 2

Answer is C. I just took the test.