Let R be the set of all real numbers. Consider the sets P = {x R : (x...
**Solution:**
To find the set (PS) Q, we need to find the elements that are common to both sets PS and Q.
**Set P:**
The equation (x - 1)(x^2 - 1) = 0 can be factorized as (x - 1)(x - 1)(x + 1) = 0. So, the solutions to this equation are x = 1 and x = -1.
Therefore, set P = {1, -1}.
**Set Q:**
The equation x^2 - 9x - 2 = 0 can be solved using the quadratic formula:
x = (-b ± √(b^2 - 4ac)) / (2a)
Plugging in the values a = 1, b = -9, and c = -2, we get:
x = (9 ± √(81 + 8)) / 2
Simplifying further, we get:
x = (9 ± √89) / 2
Therefore, the solutions to this equation are x = (9 + √89) / 2 and x = (9 - √89) / 2.
Therefore, set Q = {(9 + √89) / 2, (9 - √89) / 2}.
**Set PS:**
To find the set PS, we need to find the elements that satisfy both sets P and S.
Set S is defined as {x ∈ R : x = 5y for some y ∈ R}.
So, for an element x to be in set PS, it must satisfy both the conditions x ∈ P and x ∈ S.
For x = 1, it satisfies the condition x ∈ P but not the condition x ∈ S.
For x = -1, it satisfies the condition x ∈ P but not the condition x ∈ S.
Therefore, the set PS = ∅ (empty set).
**Set (PS) Q:**
Now, we need to find the elements that are common to both sets PS and Q.
Since the set PS is empty, there are no elements common to both PS and Q.
Therefore, the set (PS) Q = ∅ (empty set).
Hence, the correct option is (B) exactly three elements.