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