Question

Phân tích đa thức thành nhân tử

a) 5a( x-3y ) + 8(3y - x)

b) 7x^{2 -14xy + 7y2-}7z²

Answer 1

a) \(5a\left(x-3y\right)+8\left(3y-x\right)\)

\(=5a\left(x-3y\right)-8\left(x-3y\right)\)

\(=\left(x-3y\right)\left(5a-8\right)\)

b) \(7x^2-14xy+7y^2-7z^2\)

\(=7\left(x^2-2xy+y^2-z^2\right)\)

\(=7\left[\left(x^2-2xy+y^2\right)-z^2\right]\)

\(=7\left[\left(x-y\right)^2-z^2\right]\)

\(=7\left(x-y-z\right)\left(x-y+z\right)\)

Answer 2

a) 5a(x-3y) + 8(3y-x)

= 5a(x-3y) - 8(x-3y)

=(5a-8)(x-3y)

Answer 3

b) 7x²-14xy+7y² -7z²

= 7(x²-2xy+y²-z²)

=7((x-y)² - z²)

=7(x-y-z)(x+y+z)

Answer 4

a)=5a(x-3y)-8(x-3y)

=(x-3y)(5a-8)

b)=7(x²-2xy+y²-z²)

=7[(x2-2xy+y²)-z²

=7[(x-y)²-z^2]

=7(x-y-z)(x-y+z)