Question

phân tích thành nhân tử  

 a)3x^2+6xy+3y^2-3z^2                        b) x^2-2xy+y^2-z^2 + 2zt - t^2

Answer 1

a, 3( x² +2xy + y² - z²) = 3((x+y)² - z²) = 3( x+y-z)(x+y+z)

b, (x-y)² - (z-t)² = (x-y+z-t)(x-y-z+t)

Answer 2

a/3x^2+6xy+3y^2-3z^2

=3(x^2+2xy+y^2-z^2)

=3[(x+y)^2-x^2)]

=3(x+y-z)(x+y+z)

b/x^2-2xy+y^2-z^2+2zt-t^2

=(x-y)^2-(z-t)^2

=(x-y+z-t)(x-y-z+t)