Mình thu gọn 2 đa thức trước r mới cộng nhé
\(P\left(x\right)=3x^2+7+2x^4-3x^2-4-5x+2x^3\)
\(P\left(x\right)=\left(3x^2-3x^2\right)+\left(7-4\right)+2x^4-5x+2x^3\)
\(P\left(x\right)=2x^4+2x^3-5x+3\)
\(Q\left(x\right)=-3x^3+2x^2-x^4+x+x^3+4x-2+5x^4\)
\(Q\left(x\right)=\left(-3x^3+x^3\right)+2x^2+\left(-x^4+5x^4\right)+\left(x+4x\right)-2\)
\(Q\left(x\right)=-2x^3+4x^4+2x^2+5x-2\)
\(P\left(x\right)+Q\left(x\right)=2x^4+2x^3-5x+3-2x^3+4x^4+2x^2+5x-2\)
\(P\left(x\right)+Q\left(x\right)=\left(2x^4+4x^4\right)+\left(2x^3-2x^3\right)+\left(-5x+5x\right)+\left(3-2\right)+2x^2\)
\(P\left(x\right)+Q\left(x\right)=6x^4+1+2x^2\)