Question

(2a2 + ab + 2b) + (4a2 − 3ab + 9)

Answer 1

=2a^2+ab+2b+4a^2+−3ab+9
Combine likes terms:
=2a^2+ab+2b+4a^2+−3ab+9
=(2a^2+4a^2)+(ab+−3ab)+(2b)+(9)
=6a^2+−2ab+2b+9
Your answer is:
=6a^2−2ab+2b+9

Answer 2

$(2a^2 + ab + 2b) + (4a^2 - 3ab + 9) \\ \\ 2a^2 + ab + 2b + 4a^2 - 3ab + 9 \\ \\ (2a^2 + 4a^2) + (ab - 3ab) + 2b + 9) \\ \\ 6a^2 - 2ab + 2b + 9$

The answer is 6a^2 - 2ab + 2b + 9.