Question

Factorise the following
expressions.
y² - 4 =​

Answer 1

${y}^{2} - 4 \\ = {y}^{2} - {2}^{2} \\ = (y + 2)(y - 2) \\ \\formula \: used \\ ( {a}^{2} - {b) }^{2} = (a + b)(a - b)$