Question

Answer 1

Câu 1: 

a: =x(x-3)+y(x-3)

=(x-3)(x+y)

b: \(=3x\left(x-y\right)-5\left(x-y\right)=\left(x-y\right)\left(3x-5\right)\)

c: \(=\left(x-y\right)^2-\left(z-t\right)^2\)

\(=\left(x-y-z+t\right)\left(x-y+z-t\right)\)

d: \(=3\left(x^2+2xy+y^2-z^2\right)\)

\(=3\left(x+y+z\right)\left(x+y-z\right)\)

e: \(=\left(3x-2y\right)^3\)

f: \(=\left(a-1\right)\left(a^2+a+1\right)+\left(a-1\right)\left(5a+5\right)+3\left(a-1\right)\)

\(=\left(a-1\right)\left(a^2+a+1+5a+5+3\right)\)

\(=\left(a-1\right)\left(a^2+6a+9\right)=\left(a-1\right)\left(a+3\right)^2\)