Question 125705
let numbers be {{{x}}} and {{{y}}}

if the sum of two numbers is {{{33}}}, we have:

{{{x+y=33}}} 

if their difference is {{{9}}}, then we have:

{{{x-y=9}}} 


 to find out what are the two numbers, solve this system:

{{{x+y=33}}}...........(1) 
{{{x-y=9}}} ............(2)



solve (1) for {{{x}}}

{{{x+y=33}}}...........(1) 

{{{x= 33 -y}}}...........substitute in (2)


{{{(33 -y)-y=9}}} ............solve for {{{y}}}


{{{-y -y = 9 -33}}} 

{{{-2y =  -24}}} 

{{{y =  -24/-2}}} 

{{{y =  12}}} 

then

{{{x=  33-12}}}...........

{{{x= 21}}}...........


check:

{{{x+y=33}}}...........(1)

{{{21+12=33}}}

{{{33 = 33}}}

{{{x-y=9}}} ............(2)

{{{21-12=9}}} 

{{{9=9}}}