Bài 1:
a: \(=3xy\left(z+2\right)\)
b: \(=\left(x-3\right)\left(2+x\right)\)
c: \(=4\left(x^2-2xy+y^2-4\right)\)
\(=4\left(x-y-2\right)\left(x-y+2\right)\)
d: \(=5x\left(x+y\right)-\left(x+y\right)=\left(x+y\right)\left(5x-1\right)\)
e: \(=5\left(x^2-2xy+y^2-4z^2\right)\)
\(=5\left(x-y-2z\right)\left(x-y+2z\right)\)
f: \(=\left(x+y\right)^3\)