`a)x³+6x²+12x+8`
`=x³+3.x².2+3.x.2²+2³`
`=(x+2)³`
`b)x³-3x²+3x-1`
`=x³-3.x².1+3.x.1²-1³`
`=(x-1)³`
`c)1-9x+27x²-27x³`
`=1³-3.1².3x+3.1.(3x)²-(3x)³`
`=(1-3x)³`
`d)x³+3/2x²+3/4x+1/8`
`=x³+3.x². 1/2+3.x. (1/2)^2+(1/2)^3`
`=(x+1/2)^3`
`e)27x³-54x²y+36xy²-8y³`
`=(3x)³-3.(3x)².2y+3.3x.(2y)²-(2y)³`
`=(3x-2y)³`