a) -q^3 +12q^2.x – 48qx^2 +64x^3
b) a^3.b^2 +18a^2.b^2 +108ab^2 +216b^2
c) 64xy- 96x^2.y+ 48x^3.y – 8x^4.y
d) x^3+ 9x^2.y+ 27xy^2+ 27y^3
e) x^3 – 3x^2 + 3x – 1
g) 2x^3 – 6x
a) -q^3 +12q^2.x – 48qx^2 +64x^3 b) a^3.b^2 +18a^2.b^2 +108ab^2 +216b^2 c) 64xy- 96x^2.y+ 48x^3.y – 8x^4.y d) x^3+ 9x^2.y+ 27xy^2+ 27y^3 e) x^3 – 3x^2
By Rose
Đáp án:
a, ` -q^3 +12q^2.x – 48qx^2 +64x^3`
`= -[q^3 – 12q^2.x + 48qx^2 +64x^3]`
`=-[ q^3 – 3.q^2 .4x + 3.q.(4x)^2 + (4x)^3]`
`= -(q – 4x)^3`
b, `a^3.b^2 +18a^2.b^2 +108ab^2 +216b^2`
`=b^2(a^3 + 18a^2 + 108a + 216)`
`= b^2(a^3 + 3.a^2 .6 + 3.a.6^2 + 6^3)`
`= b^2(a + 6)^3`
c, `64xy- 96x^2.y+ 48x^3.y – 8x^4.y`
`= 8xy(8 – 12x + 6x^2 – x^3)`
`= 8xy(2^3 – 3.2^2 .x + 3.2.x^2 – x^3)`
`= 8xy(2 – x)^3`
d, ` x^3+ 9x^2.y+ 27xy^2+ 27y^3`
`= x^3 + 3.x^2 .3y + 3.x . (3y)^2 + (3y)^3`
`= (x + 3y)^3`
e, `x^3 – 3x^2 + 3x – 1`
`= x^3 – 3.x^2 . 1 + 3.x . 1^2 – 1^3`
`= (x – 1)^3`
g, `2x^3 – 6x`
`= 2x(x^2 – 3)`
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