Question 981831
Try taking the difference of these two:

a+b=13, b+c=14


{{{b+c-(a+b)=14-13}}}
{{{b+c-a-b=1}}}
{{{c-a=1}}}, and see this equation only has variables c and a.


Combine processes to solve to include the other equation with only c and a,
{{{c+a=15}}}


You have a simple system of
{{{system(c-a=1,c+a=15)}}}


Finishing steps:
{{{c-a+c+a=1+15}}}
{{{2c=16}}}
{{{highlight(c=8)}}}