Question 981026
{{{sqrt(x+y)=11}}}
{{{sqrt(x-y)=7}}}
Square both sides of each equation.
{{{x+y=121}}}
{{{x-y=49}}}
Now add,
{{{x+y+z-y=121+49}}}
{{{2x=170}}}
{{{x=85}}}
Then,
{{{85+y=121}}}
{{{y=36}}}