Respuesta :

remember to distribute invibile -1
simlify 2nd part
-(a^2-3a+7)=-1(a^2-3a+7)=-a^2+3a-7

now we have
3a^2+2a-2-a^2+3a-7=
3a^2-a^2+2a+3a-2-7=
2a^2+5a-9