`#Sad`
`6)`
`a,`
`8x^3-64`
`= (2x)^3-4^3`
`= (2x-4)(4x^2+8x+16)`
`b,`
`1+8x^6y^3`
`= 1^3+(2x^2y)^3`
`= (1+2x^2y)(1-2x^y+4x^4y^2)`
`c,`
`125x^3+1`
`= (5x)^3+1^3`
`= (5x+1)(25x^2-5x+1)`
`d)`
`8x^3-27`
`= (2x)^3-3^3`
`= (2x-3)(4x^2+6x+9)`
`e)`
`27x^3+(y^3)/8`
`= (3x)^3+(y/2)^3`
`= (3x+y/2)(9x^2-(3)/(2)xy+(y^2)/4)`
`f,`
`125x^3+27y^3`
`= (5x)^3+(3y)^3`
`= (5x+3y)(25x^2-15xy+9y^2)`
`7)`
`a,`
`x^3+6x^2+12x+8`
`= x^3+3. x^2. 2+3. x. 2^2+2^3`
`= (x+2)^2`
`b,`
`x^3-3x^2+3x-1`
`= x^3-3. x^2. 1+3. x. 1-1^3`
`= (x-1)^3`
`c,`
`1-9x+27x^2-27x^3`
`= 1^3-3. 1^2. 3x+3. 1. 9x^2-(3x)^3`
`= (1-3x)^3`
`d,`
`x^3+(3)/(2)x^2+(3)/(4)x+1/8`
`= x^3+3. x^2. 1/2+3. x. 1/4+(1/2)^3`
`= (x+1/2)^3`
