P= (-2x)^2 +3x^4 +x^3 + x^2-1/4x
Q= 3x^4 +3x^2-1/4-4x^3 -2x^2
a. 
sắp xếp các đa thức
P = 3x^4 +x^3+3x^2 -1/4x
Q = 3x^4-4x^3 +x^2-1/4
b. 
P+Q =  3x^4 +x^3+3x^2 -1/4x + 3x^4-4x^3 +x^2-1/4
=6x^4 -3x^3 +4x^2 -1/4x-1/4 
 

a/ P= ( -2x^2 + x^2 ) + 3x^4+ x^3  - 1/4x
= - x^2 + 3x^4+ x^3  - 1/4x
= 3x^4+ x^3 - x^2 - 1/4x ( bậc 4  )
Q= 3x^4 +3x^2 -1/4 -4x^3 -2x^2
= 3x^4 +(3x^2-2x^2 )-1/4 -4x^3
= 3x^4 +x^2 -1/4 -4x^3
= 3x^4 -4x^3 +x^2 -1/4 ( bậc 4 )
b/ 
P+Q =​  3x^4+ x^3 - x^2 - 1/4x  + 3x^4 -4x^3 +x^2 -1/4
P-Q = 3x^4+ x^3 - x^2 - 1/4x  - 3x^4 -4x^3 +x^2 -1/4
c/  (dấu . là dấu nhân )
P(1) = 3.1^4 +1^3-1^2-1/4.1 + 3.1^4 -4.1^3 +1^2 -1/4 .1
P(2) = 3.2^4 +2^3-2^2-1/4.2 + 3.2^4 -4.2^3 +2^2 -1/4 .2
P(-3) = 3.(-3)^4 -3^3+3^2-1/4.(-3) + 3.(-3)^4 -4.(-3)^3 -3^2 -1/4 .(-3)
Q(-1)= 3.(-1 )^4 -1^3+1^2-1/4.(-1) + 3.(-1)^4 -4.(-1)^3 -1^2 -1/4 .(-1)
Q(-2)= 3.(-2 )^4 -1^3+2^2-1/4.(-2) + 3.(-2)^4 -4.(-2)^3 -1^2 -1/4 .(-2)
Q(-3) = 3.(-3)^4 -3^3+3^2-1/4.(-3) + 3.(-3)^4 -4.(-3)^3 -3^2 -1/4 .(-3)