Question

Помогите ))))))))))))))))

Answer 1

=a^2*b*c+2*a^2*b*c-3*a^2*b*c=3*a^2*b*c-3*a^2*b*c=0
2) = -a^3*b+7*a^2*b+a^3*b=7*a^2*b
3) =7*a^2-3*a^2-4a^2=4*a^2-4*a^2=0.