Respuesta :

marcthemathtutor

Answer:

= 10x² + 9x³

Step-by-step explanation:

I'm assuming you mean question 19

3x² + 5x³ + 7x² + 4x³    (rearrange to group like terms)

=3x² + 7x² + 5x³ + 4x³  (factor out common powers)

= (3+7)x² + (5+4)x³

= 10x² + 9x³