Question 986550
You are told the total number of cans + bottles = 910. You are also told there are x cans.
So that means there are (910-x) bottles

The weight of total of both cans and bottles is
{{{14cans + 70bottles = weight}}}
{{{14x + (70(910-x)) = weight}}}
{{{14x + 63700 - 70x = weight}}}
{{{63700 - 56x = weight}}}