\(a,=5\left(x-4y\right)\\ b,=\left(3x+y\right)^2\\ c,=3\left(x^2-y^2\right)-12\left(x-y\right)\\ =\left(x-y\right)\left[3\left(x+y\right)-12\right]\\ d,=25-\left(x^2-4xy+4y^2\right)\\ =25-\left(x-2y\right)^2\\ =\left(5-x+2y\right)\left(5+x-2y\right)\\ e,=x^2-4x-x+4\\ =x\left(x-4\right)-\left(x-4\right)\\ =\left(x-1\right)\left(x-4\right)\)