# How do you find the product of (-m+5n)(-m-5n)?

${m}^{2} - 25 {n}^{2}$
$\left(- m + 5 n\right) \left(- m - 5 n\right) = \left(- m\right) \left(- m\right) - m \left(- 5 n\right) + 5 n \left(- m\right) + 5 n \left(- 5 n\right) = {m}^{2} + 5 m n - 5 m n - 25 {n}^{2} = {m}^{2} - 25 {n}^{2}$