Answer:
[tex]3x^{3} + 7x^{2} - 8x[/tex]
Step-by-step explanation:
[tex]p(x) + q(x) - r(x)[/tex]
[tex](5x^{3} + 3x^{2} - 6x - 4) - (3x^{3} -2x^{2} - x + 3) + (x^{3} + 2x^{2} - 3x + 7)[/tex]
[tex]5x^{3} + 3x^{2} - 6x - 4 - 3x^{3} + 2x^{2} + x - 3 + x^{3} + 2x^{2} - 3x + 7[/tex]
[tex]3x^{3} + 7x^{2} - 8x[/tex]
