Question

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

Answer 1

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

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

Ответ: $(8;-1)$