Question

Factor k^2-81...............

Answer 1

Answer:

$(k+9)(k-9)$

Step-by-step explanation:

$k^2-81$

$k^2-9^2$

Apply the difference of squares formula: $x^2-y^2=\left(x+y\right)\left(x-y\right)$

Thus, $k^2-9^2=\left(k+9\right)\left(k-9\right)$