Решите систему уравнений: х+у=1 х^2-y^2=9

Х^2 - y^2 = 9 ( x - y )•( x + y ) = 9 X + y = 1 X - y = 9 2x = 10 X = 5 5 + y = 1 y = - 4 Проверка 5 + ( - 4 ) = 1 1 = 1 5^2 - ( - 4 )^2 = 9 25 - 16 = 9 9 = 9 ОТВЕТ ( 5 ; - 4 )

[latex] \left \{ {x+y=1 } \atop {x^2-y^2=9}} \right. [/latex] [latex] \left \{ {{{x+y = 1}} \atop { x^2 = y^2+9}} \right. [/latex] [latex] \left \{ {{{x+y = 1}} \atop { (x-y) (x+y) = 9}} \right. [/latex] [latex] \left \{ {{{y = 1-x}} \atop { x^2-y^2 = 9}} \right. [/latex] [latex] \left \{ {{x = 5 } \atop { y = -4}} \right. [/latex] График внизу если надо