\(K\left(x\right)+L\left(x\right)=\left(x^3-mx+m^2\right)+\left[\left(m+1\right)x^2+3mx+m^2\right]\)
\(K\left(x\right)+L\left(x\right)=x^3-mx+m^2+\left(m+1\right)x^2+3mx+m^2\)
\(K\left(x\right)+L\left(x\right)=\left[x^3+\left(m+1\right)x^2\right]-\left(mx-3mx\right)+\left(m^2+m^2\right)\)
\(K\left(x\right)+L\left(x\right)=x^2\left[x+\left(m+1\right)\right]+2mx+2m^2\)