Question

3а (а+2)-(а+3)в квадрате

Answer 1

3а²+6а -(а²+6а+9)= 3а²+6а -а²-6а- 9 = 2а²-9

Answer 2

$3a(a+2)-(a+3)^{2}=3a^{2}+6a-(a^{2}+6a+9)=3a^{2}+6a-a^{2}-6a-9=(3a^{2}-a^{2})+(6a-6a)-9=2a^{2}-9$