Subtract 3x^2 - 2x + 1 from 5x^2 + 3x -7
\((5x^2 + 3x -7) - (3x^2 - 2x + 1)\)\(5x^2 + 3x -7 - 3x^2 + 2x - 1\)\(5x^2 - 3x^2 + 3x +2x - 7 - 1\)\(2x^2 + 5x - 8\)
\(5x^2 + 3x -7-(3x^2 - 2x + 1)=\\ 5x^2+3x-7-3x^2+2x-1=\\ 2x^2+5x-8\)