a) 6x^2 + 3x^4 + 3x^3 = x^2 ( 6 + 3x^2 + 3x )
b) ( x^2 + 3 ) ( 2x - 1 ) + ( x^2 + 3 ) ( x - 3 ) =
x^2 ( 3 ( 2x - 1 )) + ( 3 ( x - 3 )) =
x^2 ( 6 ( 3x - 2 ))
c) ( x - 2 ) ( 2x^2 + 5 ) - ( x - 2 ) x^2 =
x^2 ( 2 + 5 ) = x^2 ( 7 )
d) ( x - 2 ) ( 4x^2 + 1 ) + 2x^2 ( 2 - x ) =
x^2 ( 4 + 1 ) + 2 = x^2 ( 5 ) + 2
