Question

Phân tích đa thức thành nhân tử :

1. x²-9

2. -2x²+2x+12

3. x⁴+2016x²+2015+2016

4. -2x²+2x+24

5. x⁴+2015x²+2014x+2015

6. x²-5x+4

7. x³+x(3xy+3xz+2yz)+y³+y(3yx+3yz+2xz)+z³+z(3zx+3zy+2xy)

8. x²-7x+6

9. x²+5x+4

10. x²+7x+6
 

Answer 1

1.x²-9

= (x-3)(x+3)

2. -2x²+2x+12

= -2x²+6x-4x+12

= -2x(x+2)+6(x+2)

= (x+2)(-2x+6)

4. -2x²+2x+24

= -2x²+8x-6x+24

= -2x(x+3)+8(x+3)

= (x+3)(-2x+8)

6. x²-5x+4

= x²-4x-x+4

= x(x-1) -4(x-1)

= (x-1)(x-4)

8. x²-7x+6

= x²-6x-x+6

= x(x-1)-6(x-1)

= (x-1)(x-6)

9. x²+5x+4

= x²+4x+x+4

= x(x+1)+4(x+1)

=(x+1)(x+4)

10. x²+7x+6

= x² +x+6x+6

= x(x+1)+6(x+1)

= (x+6)(x+1)

K nhé

Answer 2

Cảm ơn nhìu

Answer 3

7. x³+x(3xy+3xz+2yz)+y³+y(3yx+3yz+2xz)+z³+z(3zx+3zy+2xy)

= x³+3x²y+3x²z+2xyz+y³+3y²x+3y²z+2xyz+z³+3z²x+3z²y+2xyz

= (x³+3x²y+3xy²+y³)+z³+(3x²z+6xyz+3y²z)+3xz²+3yz²

= (x+y)³+z³+3(x+y)²z+3(x+y)z²

= (x+y+z)³