If (5)(x^2) has four different prime factors, at most how many different prime factors does x have? Pick one
A) 1 B) 2 C) 3 D) 4 E) 5
x can have at most 4 prime factors, namely the prime factor 5 plus 3 others.   If x had more than this number of prime factors, then (5)(x^2) would have more than 4 prime factors.   The answer is 4.
<result>D</result>
If (5)(x^2) has four different prime factors, at most how many different prime factors does x have?