Question

Bài 1: Phân tích đa thức thành nhân tử.
a) A = 3x² + 6xy + 3y² - 3z²
b) A = ( x + y )² - 2 ( x + y ) + 1
c) A = x² + y² + 2xy + yz + zx

Answer 1

a)\(A=3x^2+6xy+3y^2-3z^2=3\left(x^2+2xy+y^2-z^2\right)=3\left[\left(x+y\right)^2-z^2\right]=3\left(x+y-z\right)\left(x+y+z\right)\)b) \(A=\left(x+y\right)^2-2\left(x+y\right)+1=\left(x+y-1\right)^2\)

c) \(A=x^2+y^2+2xy+yz+zx=\left(x+y\right)^2+z\left(x+y\right)=\left(x+y\right)\left(x+y+z\right)\)