Answer:
(y - 3)(y + 1)
Step-by-step explanation:
Given
(y - 1)² - 4 ← this is a difference of squares and factors in general as
a² - b² = (a - b)(a + b), thus
(y - 1)² - 4
= (y - 1)² - 2²
= (y - 1 - 2)(y - 1 + 2)
= (y - 3)(y + 1) ← in factored form
