Question 933025

the sum is {{{14}}}:

{{{x+y=14}}}.....eq.1  

and the difference is {{{4}}}:

{{{x-y=4}}}.....eq.2

system is:
{{{x+y=14}}}.....eq.1
{{{x-y=4}}}.....eq.2
_____________________ to solve, add eq.1 and eq.2

{{{x+cross(y)+x-cross(y)=14+4}}}

{{{2x=18}}}

{{{x=9}}}

go to {{{x+y=14}}}.....eq.1 substitute {{{9}}} for {{{x}}} and solve for {{{y}}}

{{{9+y=14}}}

{{{y=14-9}}}

{{{y=5}}}