Question

Помогите решить систему уравнений

Answer 1

$left { {{x^2-y^2=72} atop {x+y=9}} right. left { {{(x+y)(x-y)=72} atop {(x+y)=9}} right. left { {{9(x-y)=72} atop {x+y=9}} right. left { {{x-y=8} atop {x+y=9}} right.|+ left { {{x-y=8} atop {2x=17}} right. left{ {{8.5-y=8}atop{x=8.5}}right.left{{{y=0.5} atop{x=8.5}} right.$
Ответ: $(8.5;0.5)$