a^2 - b^2 = (a + b)(a - b)
In this case
49x^4y^2 - 4z^2
= (7x^2y)^2 - (2z)^2
= (7x^2y + 2z)(7x^2y - 2z)
Factors are (7x^2y + 2z) and (7x^2y - 2z)
Answer:
D) 7x^2y + 2z
