$$\\p(x) = (7x^3+24x^2+25x+1)\quad -\quad (x^5+3x^3+9x)\\ p(x) = 7x^3+24x^2+25x+1\quad -x^5-3x^3-9x\\ p(x) = -x^5+7x^3-3x^3+24x^2+25x-9x+1\quad \\ p(x) = -x^5+4x^3+24x^2+16x+1\quad \\$$