(7xy – 1) (7xy + 1) = …………………. A) 49x2 y2 – 1 B) 4

1.	(7xy – 1) (7xy + 1) = …………………. A) 49x2 y2 – 1 B) 49xy- 1 C) 49xy2 – 1 D) 9xy -1
Answer» A) 49x² y² – 1 Correct option is (A) 49x²y² – 1 (7xy – 1) (7xy + 1) \(=(7xy)^2-1^2\) = \(49x^2y^2–1\)

(7xy – 1) (7xy + 1) = …………………. A) 49x2 y2 – 1 B) 49xy- 1 C) 49xy2 – 1 D) 9xy -1

Answer»

A) 49x² y² – 1

Correct option is (A) 49x²y² – 1

(7xy – 1) (7xy + 1) \(=(7xy)^2-1^2\)

= \(49x^2y^2–1\)