Question

factor completely.
d^2 - 1

Explanation:

Step1: Recognize difference - of - squares formula

The expression $d^{2}-1$ is in the form $a^{2}-b^{2}$, where $a = d$ and $b = 1$. The difference - of - squares formula is $a^{2}-b^{2}=(a + b)(a - b)$.

Step2: Apply the formula

Substitute $a = d$ and $b = 1$ into the formula. So $d^{2}-1=(d + 1)(d - 1)$.

Answer:

$(d + 1)(d - 1)$