a) Xắp xếp :
. P(x)=x^3 + 2x^2 +3x +5x-1
=>P(x)=x^3 + 2x^2 +8x-1
. Q(x)=x^3+2x +x^3+ 2x^2 +3
=> Q(x)=2x^3 + 2x^2 +2x+3
b) H(x)= P(x)-Q(x)
<=> H(x) =( x^3 + 2x^2 +8x-1)- ( 2x^3 + 2x^2 +2x+3)
<=>H(x)=x^3 + 2x^2 +8x-1- 2x^3 - 2x^2 -2x -3
<=>H(x)=- x^3 +6x-4
Học tốt!!!