`M+N= 0,5x^4 -4x^3 +2x-2,5 + 2x^3 +x^2+1,5`
`= 0,5x^4 +(-4x^3+ 2x^3 ) +x^2+2x +(-2,5 +1,5)`
`= 0,5x^4 -2x^3 +x^2+2x -1`
\(M+N=0,5x^4-4x^3+2x-2,5+2x^3+x^2+1,5\)
\(=0,5x^4-4x^3+2x^3+x^2+2x-2,5+1,5\)
\(=0,5x^4-2x^3+x^2+2x-1\)
\(M+N=\left(0,5x^4-4x^3+2x-2,5\right)+\left(2x^3+x^2+1,5\right)\)
\(=0,5x^4-4x^3+2x-2,5+2x^3+x^2+1,5\)
\(=0,5x^4-\left(4x^3-2x^3\right)+x^2+2x-\left(2,5-1,5\right)\)
\(=0,5x^4-2x^3+x^2+2x-1\)