Question

1+4+7+...+x=425
X-?

Answer 1

Ответ:

1)12+х+х=425

12+2х=425

2х=425-12

2х=413

х=206.5

2)12+206.5+х=425

х=425-206.5-12

х=206.5

1+4+7+206.5+206.5=425

12+413=425

425=425