Bài 1
a
\(=2x^3+x\)
b
\(=5x^5-x^3-\dfrac{1}{2}x^2\)
c
\(=-3x^4y^2+6x^3y^2\)
d
\(=2a^3x^3+3a^2bx^2-2a^2cx\)
e
\(=6x^2-2x-6x^2-6x+3+8x\\ =3\)
2:
a: =x^3+x^2y-x^2y+y^3=x^3+y^3=1+1000=1001
b: =>\(x^3-x^2+x-x^3-x^2+m-5=-2x^2+x\)
=>m-2x^2+x-5=-2x^2+x
=>m=5
c: M=0
=>12x^2+8x-12x^2-30x+21x-21=0
=>-x-21=0
=>x=-21
d: x=2021 nên x+1=2022
x^4-2022x^3+2022x^2-2022x+2022
=x^4-x^3(x+1)+x^2(x+1)-x(x+1)+x+1
=x^4-x^4-x^3+x^3+x^2-x^2-x+x+1
=1