(x+y)^2 - z^2 = (x+y+z)(x+y-z)
(2p-m)^2 - (p+2m)^2 = (2p-m+p+2m)(2p-m-(p+2m)) = (3p+m)(p-3m)
25z^2 - (2t+3z)^2 = (5z+2t)(5z-2t + 3z)
(x+y)^2 - z^2 = (x+y+z)(x+y-z)
(2p-m)^2 - (p+2m)^2 = (2p-m+p+2m)(2p-m-(p+2m)) = (3p+m)(p-3m)
25z^2 - (2t+3z)^2 = (5z+2t)(5z-2t + 3z)