Решить систему уравнений: {x^2-y^2=63 x+y=7

$\left \{ {{x^2-y^2=63} \atop {x+y=7}} \right.; \left \{ {{(x-y)(x+y)=7*9} \atop {x+y=7}} \right.; \left \{ {{(x-y)*7=7*9} \atop {x+y=7}} \right.; \left \{ {{x-y=9} \atop {x+y=7}} \right.;$

$\left \{ {{x-y=9} \atop {x+y+x-y=7+9}} \right.; \left \{ {{x-y=9} \atop {2x=16}} \right.; \left \{ {{y=x-9} \atop {x=8}} \right.; \left \{ {{y=8-9} \atop {x=8}} \right. \left \{ {{x=8} \atop {y=-1}} \right.$

Ответ: $(8;-1)$