`5x^3 (2x^3 - x^2 + 6x -3)`
`=10x^6-5x^5+30x^3-15x^3`
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`(x+3) (x^2 - 3x + 9) - x ( x^2 + 6)`
`= x^3+27-x^3+6x`
`=6x+27`
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`(x-2)^3 - (x+2)^3 + 12 (x-1) (x+1)`
`=x^3-6x^2+12x-8 -(x^3+6x^2+12x+8)+12(x^2-1)`
`=x^3-6x^2+12x-8 -x^3-6x^2-12x-8+12x^2+12`
`=-8-8+12`
`=-4`