Question

phân tích đa thức thành nhân tử

a) 6x - 9 - x² =

b) 9x² + 6xy + y² =

c) ( x + y )² - ( x - y ) ² =

d) x² - 2xy + y² - z² =

e) 16x - 5x² - 3 =

f) x² + 4x + 3 =

Answer 1

a, \(6x-9-x^2\Leftrightarrow-\left(x^2-2.x.3+3^2\right)\Leftrightarrow-\left(x-3\right)^2\)

Answer 2

d, \(x^2-2xy+y^2-z^2\Leftrightarrow\left(x^2-2xy+y^2\right)-z^2\Leftrightarrow\left(x-y\right)^2-z^2\Leftrightarrow\left(x-y+z\right)\left(x-y-z\right)\)

Answer 3

b, \(9x^2+6xy+y^2\Leftrightarrow\left(3x\right)^2+2.3x.y+y^2\Leftrightarrow\left(3x+y\right)^2\)

Answer 4

, \(\left(x+y\right)^2-\left(x-y\right)^2\Leftrightarrow\left(x+y+x-y\right)\left(x+y-x+y\right)\Leftrightarrow2x.2y\Leftrightarrow4xy\)

Answer 5

f, \(x^2+4x+3\Leftrightarrow\left(x^2+2.x.2+2^2\right)-4+3\Leftrightarrow\left(x+2\right)^2-1^2\Leftrightarrow\left(x+2+1\right)\left(x+2-1\right)\Leftrightarrow\left(x+3\right)\left(x-1\right)\)