If they both buy milk from diff store still graph and equations are same. sam's graph will come also same,as u plugin some values in equation and if minimum number of gallon we assume=1 then lowest cost should be 3.4$ which comes same for both
After adding 4x you will get 10= 6x+6. Next, you subtract 6 on both sides which will leave you with. 4=6x you then divide the 6 to the 4. You can also reduce which will give you the answer 2/3.