Question

-(а+2,1б)+(3,8а-1,9б)

Answer 1

-(а+2,1б)+(3,8а-1,9б)=-а-2,1б+3,8а-1,9б=2,8а-4б

Answer 2

Спасибо

Answer 3

-(а+2,1b)+(3,8а-1,9b)=-а-2.1b+3.8а-1.9b=2.8а-4b