Answer:
= 10x² + 9x³
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
6.5m questions
8.6m answers