a) x ( $2x^{2}$ - 3 ) - $2x^{2}$ ( 5x + 1 ) + $2x^{2}$
= $2x^{3}$ - 3x - $2x^{2}$ - $10x^{3}$ + $2x^{2}$ + $2x^{2}$
= - $8x^{3}$ - 3x + $2x^{2}$
b) 3x ( x - 2 )-5x ( 1 - x )-8 ($x^{2}$ - 3)
= $3x^{2}$ - 6x -5x -$5x^{2}$ - $8x^{2}$ + 24
= - $10x^{2}$ -11x + 24
c) (x+3) ($x^{2}$ -3x+9)-(54+$x^{3}$ )
= $x^{3}$ -$3x^{2}$ + 9x + $3x^{2}$ - 9x + 27 - 54 - $x^{3}$
= 27
d)( 2x + y )( $4x^{2}$ - 2xy + $y^{2}$)-( $4x^{2}$ +2xy+$y^{2}$ )
= $8x^{3}$ - $4x^{2}$y + $2xy^{2}$ + $4x^{2}$y - $4x^{2}$ - 2xy - $y^{2}$
= $8x^{3}$ + $2xy^{2}$ - $4x^{2}$ - 2xy - $y^{2}$