$a)$
$A(x+) + B(x0 = (x^5 - 4x^3 + x^2 - 2x +1) + (x^5 - 2x^4 + x^2 - 5x + 3)$
$= x^5 - 4x^3 + x^2 - 2x +1 + x^5 - 2x^4 + x^2 - 5x + 3$
$= (x^5 + x^5) - 2x^4 - 4x^3 + (x^2 + x^2) - (2x +5x) + (1+3)$
$= 2x^5 - 2x^4 - 4x^3 + 2x^2 - 7x + 4$
$b) $
$A(1) = 1^5 - 4.1^3 +1^2 - 2.1 + 1$
$= 1 - 4 +1 - 2 + 1 $
$= -3$
$\text{@Team IQ vô cực}$