Question 732411

let integers be {{{x}}} and {{{y}}}

given: if {{{x<y}}}, then

{{{x+20=y}}}.......eq.1

{{{x+y=40}}}.......eq.2
____________________________solve system 


{{{x+20=y}}}.......eq.1...solve for {{{x}}}

{{{x=y-20}}}..substitute in eq. 2


{{{(y-20)+y=40}}}.......eq.2...solve for {{{y}}}

{{{2y-20=40}}}

{{{2y=40+20}}}

{{{2y=60}}}

{{{y=60/2}}}

{{{highlight(y=30)}}}

go back to {{{x=y-20}}} and find {{{x}}}

{{{x=30-20}}}

{{{highlight(x=10)}}}