Решите систему уравнений x+y=7 x^2-y^2=21

[latex] \left \{ {{x+y=7} \atop {x^2-y^2=21}} \right. [/latex] [latex] \left \{ {{x+y=7} \atop {(x-y)(x+y)=21}} \right. [/latex] [latex] \left \{ {{x+y=7} \atop {(x-y)*7=21}} \right. [/latex] [latex] \left \{ {{x+y=7} \atop {x-y=3}} \right. [/latex] [latex] \left \{ {{2x=10} \atop {y=x-3}} \right. [/latex] [latex] \left \{ {{x=5} \atop {y=5-3}} \right. [/latex] [latex] \left \{ {{x=5} \atop {y=2}} \right. [/latex] Ответ: (5;2)