Answer:
(2x + y)(2x - y - 1)
Explanation:
4x² - y² - 2x - y
4x² - y² is a difference of squares and factors in general as
a² - b² = (a - b)(a + b) , then
4x² - y²
= (2x)² - y²
= (2x - y)(2x + y)
expression is now
(2x - y)(2x + y) - (2x + y) ← factor out (2x + y) from each term
= (2x + y)(2x - y - 1)