Question

Помогите с математикой​

Answer 1

Ответ:

1) -2,4а•(-5b)=12ab

2) 9a -a-8b+3b=8a-5b

3) a+(a -10)-(15+a)=a+(a-10)-(a+15)=2a-10-(a+15)=a-25

4)-4(b-4)+7(b+2)=-4•b+(-4•-4)+(7•b+7•2)=-4b+16+(7b+14)=3b+30