1) -20x^2 \ - \ x \ + \ 24x^3 = \ \color{red}{24x^3 - 20x^2 \ - \ x}
2) x \ -\ 2(9x^3 \ - \ x) \ - \ 13x^4 = \ \color{red}{-13x^4 - 18x^3 \ + \ 3x}
3) x \ -\ 2(16x^3 \ - \ x) \ - \ 20x^4 = \ \color{red}{-20x^4 - 32x^3 \ + \ 3x}
4) -3x^2 \ - \ 3 \ + \ 6x^3 = \ \color{red}{6x^3 - 3x^2 \ - \ 3}
5) -18x^2 \ - \ 7 \ + \ 19x^3 = \ \color{red}{19x^3 - 18x^2 \ - \ 7}
6) -2(7x^3 \ - \ x) \ - \ 9x^4 = \ \color{red}{-9x^4 - 14x^3 \ + \ 2x}
7) 16x^2 - 18x^3 = \ \color{red}{-18x^3 + 16x^2 }
8) -2(22x^3 \ - \ x) \ - \ 24x^4 = \ \color{red}{-24x^4 - 44x^3 \ + \ 2x}
9) -5x^2 \ - \ x \ + \ 9x^3 = \ \color{red}{9x^3 - 5x^2 \ - \ x}
10) -6x^2 \ - \ x \ + \ 10x^3 = \ \color{red}{10x^3 - 6x^2 \ - \ x}