Question 708718
x and y, {{{x<y}}}.


{{{x+y=12}}} and {{{y^2-x^2=48}}}


Using sum equation, x=12-y.  
We can make {{{y^2-(12-y)^2=48}}}.
{{{y^2-(144-24y+y^2)=48}}}
{{{y^2-144+24y-y^2=48}}}
{{{24y-144=48}}}
{{{24y=48+144=192}}}
y=192/24


Answer: y=8.  This make x=4.