Question

\(P\left(x\right)=x^4+3x^3-2x^5-x-\frac{1}{2}\)

\(Q\left(x\right)=\frac{1}{2}x-x^4-\frac{2}{3}x^5-2x^3\)

a) sắp xếp các đa thức theo lũy thừa giảm dần

b)P+Q vs P-Q

c)cm x=0 là nhiệm của p(x)

Answer 1

a: \(P\left(x\right)=-2x^5+x^4+3x^3-x-\dfrac{1}{2}\)

\(Q\left(x\right)=\dfrac{-2}{3}x^5-x^4-2x^3+\dfrac{1}{2}x\)

b: \(P\left(x\right)+Q\left(x\right)=-2x^5+x^4+3x^3-x-\dfrac{1}{2}-\dfrac{2}{3}x^5-x^4-2x^3+\dfrac{1}{2}x\)

\(=\dfrac{-8}{3}x^5+x^3-\dfrac{1}{2}x-\dfrac{1}{2}\)

b: \(P\left(x\right)-Q\left(x\right)=-2x^5+x^4+3x^3-x-\dfrac{1}{2}+\dfrac{2}{3}x^5+x^4+2x^3-\dfrac{1}{2}x\)

\(=-\dfrac{4}{3}x^5+2x^4+5x^3-\dfrac{3}{2}x-\dfrac{1}{2}\)