Answer:
The second choice is the correct one.
Step-by-step explanation:
20x^4 - 45x^2
GCF is 5x^2, so the factors are:
5x^2( 4x^2 - 9)
Now 4x^2 - 9 is the differencr of 2 squares:
4x^2 - 9 = (2x + 3)(2x - 3)>