a: \(=\left(m^2-2m+1\right)-\left(n^2-2np+p^2\right)\)
\(=\left(m-1\right)^2-\left(n-p\right)^2\)
\(=\left(m-1-n+p\right)\left(m-1+n-p\right)\)
b: \(=3\left(a^2-2ab+b^2-4c^2\right)\)
\(=3\left[\left(a-b\right)^2-\left(2c\right)^2\right]\)
\(=3\left(a-b-2c\right)\left(a-b+2c\right)\)