P(x) + Q(x) = 4x3 + x2 - x + 5 + ( -2 )x2 + 4x - 1
= 4x3 + ( 1 - 2 )x2 + ( 4 - 1 )x + ( 5 - 1 )
= 4x3 - x2 + 3x + 4
P(x) - Q(x) = ( 4x3 + x2 - x + 5 ) - ( -2x2 + 4x - 1 )
= 4x3 + x2 - x + 5 + 2x2 - 4x + 1
= 4x3 + ( 1 + 2 )x2 -x - 4x + ( 5 + 1 )
= 4x3 + 3x2 - 5x + 6