Question

Помогите.Срочно надо

Answer 1

1) (x-4)² -6=х² -8х+16-6=х² -8х+10
2) 10а+а² -10а+25=а² +25
3) (3m-7n)² -9m (n-5n)=9m² -42mn+49n² -9m (-4n)=9m² -42mn+49n² +36mn=9m² -6mn+49n²