(8x - 21)(8x + 21)
4. 12x^2-64x-256=4(3x^2-16x-64)
the GCF is 8x
(4x - 3)(16x^2 + 12x + 9)
The GCF is 4.
-x^6(64x^3 - 27)
(8x - 21)(8x + 21)
4. 12x^2-64x-256=4(3x^2-16x-64)
the GCF is 8x
(11x + 9)(x + 5)
(8x + 5y)(64x^2 - 40xy + 25y^2)
4096
(4x - 3)(16x^2 + 12x + 9)
6x2 + 64x - 12 = 10 ∴ 6x2 + 64x - 22 = 0 ∴ 3x2 + 32x - 11 = 0 ∴ 3x2 + 33x - x - 11 = 0 ∴ 3x(x + 11) - 1(x + 11) = 0 ∴ (3x - 1)(x + 11) = 0 ∴ x ∈ {1/3, -11}
x5 - 1024 = (x - 4)(x4 + 4x3 + 16x2 + 64x + 256)
In case you meant 64x^3 - 27y^3, that factors to (4x - 3y)(16x^2 + 12xy + 9y^2)
(4x - 3y)(16x^2 + 12xy + 9y^2)