Question

de -5x²+4x-7x³ resta x³+5x²

Answer 1

$-5 x^{2} +4x-7 x^{3} - ( x^{3} +5 x^{2} )$
$-5 x^{2} +4x-7 x^{3} - x^{3} -5 x^{2} = -8 x^{3} -10 x^{2} +4x$

Espero que te sirva :)