Question

(30X-1)+929X-2)+....+(21X-10)=710

Answer 1

(30x-1)+(29x-2)+...+(21x-10)=710

<=>[(30-10):1+1]x-(1+2+...+10)=710

<=>21x-[(10+1).10:2]=710

<=>21x-55=710

=>21x=710-55

=>21x=655

=>x=655/21

Chúc bạn học giỏi nha!!!

Answer 2

(30x-1)+(29x-2)+...+(21x-10)=710

<=>[(30-10):1+1]x-(1+2+...+10)=710

<=>21x-[(10+1).10:2]=710

<=>21x-55=710

=>21x=710-55

=>21x=655

=>x=655/21

Chúc bạn học giỏi nha!!!