Question

a2 + 5a – 7a + 8a2 – 3a – 9b + 5b + 4ab ​

Answer 1

$\bf \textcolor{blue}{a^{2} + 5a - 7a + 8a ^{2} - 3a - 9b + 5b + 4ab = } \\ \\ \bf \textcolor{red}{9a ^{2} - 5a - 4b + 4ab}$

Lasers✨