Question

Find x+y if x^-y^=120 and x-y=10

Answer 1

`\bf \begin{cases} x^2-y^2=120\\ x-y=10\implies \boxed{x}=10+y\\ ----------\\ \left( \boxed{10+y} \right)^2-y^2=120 \end{cases} \\\\\\ (10^2+20y+y^2)~~-~~y^2=120\implies 100+20y=120 \\\\\\ 20y=20\implies y=\cfrac{20}{20}\implies y=1\\\\ -------------------------------\\\\ x-y=10\implies x-(1)=10\implies x=11`