Question

Будь ласка, дужее требаа

Answer 1

$\displaystyle \left \{ {{x^2-y^2=16} \atop {\frac{x+y}{2}=4}} \right.\\\\\left \{ {{(x-y)(x+y)=16} \atop {x+y=8}} \right.\\\\(x-y)*8=16\\\\x-y=2$