1 Phân tích đa thức thành nhân tử ( phối hợp nhiều phương pháp )
a, 3x^2-6xy+3y^2 b, 12x^5y+24x4y^2+12x^3y^3
c, 64xy-96x^2y+48x^3y-8x^4y d, 54x^3+16y^3
e, x^2-2xy+y^2-4 f, -16x^2+8xy-y^2+49
Mng làm giúp mk vs ạ ! mk vote 5 sao . Mk cảm ơn tr
`a)3x^2-6xy+3y^2`
`=3(x^2-2xy+y^2)`
`=3(x-y)^2`
`b)12x^5y+24x^4y^2+12x^3y^3`
`=12x^3y(x^2+2xy+y^2)`
`=12x^3y(x+y)^2`
`c)64xy-96x^2y+48x^3y-8x^4y`
`=8xy(8-12x+6x^2-x^3)`
`=8xy(2^3-12x+6x^2-x^3)`
`=8xy(2-x)^3`
`d)54x^3+16y^3`
`=2(27x^3+8y^3)`
`=2.[(3x)^3+(2y)^3]`
`=2.(3x+2y)(9x^2-6xy+4y^2)`
`e)x^2-2xy+y^2-4`
`=(x^2-2xy+y^2)-2^2`
`=(x-y)^2-2^2`
`=(x-y-2)(x-y+2)`
`f)-16x^2+8xy-y^2+49`
`=-(16x^2-8xy+y^2)+7^2`
`=7^2-(4x-y)^2`
`=(7-4x+y)(7+4x-y)`
`a)3x^2-6xy+3y^2`
`=3(x^2-2xy+y^2)`
`=3(x-y)^2`
`b)12x^5y+24x^4y^2+12x^3y^3`
`=12x^3y(x^2+2xy+xy^2)`
`=12x^3y(x+y)^2`
`c)64xy-96x^2y+48x^3y-8x^4y`
`=8xy(8-12x+6x^2-x^3)`
`=8xy(2^3-3.2^2x+3.2.x^2-x^3)`
`=8xy(2-x)^3`
`d)54x^3+16y^3`
`=2(27x^3+8y^3)`
`=2[(3x)^3+(2y)^3]`
`=2(3x+2)(9x^2-6xy+4y^2)`
`e)x^2-2xy+y^2-4`
`=(x^2-2xy+y^2)-4`
`=(x-y)^2-2^2`
`=(x-y+2)(x-y-2)`
`f)-16x^2+8x-y^2+49`
`=49-(16x^2-8x+y^2)`
`=7^2-(4x-y)^2`
`=(7+4-y)[7-(4-y)]`
`=(7+4-y)(7-4+y).`