Question

x+y=10
x-y=2
решите систему уравнений

Answer 1

$- left { {{big{x+y=10}} atop {big{x-y=2}}} right. \ \ \ x+y-x+y=10-2 \ 2y=8 \ y=4 \ \ x=10-y \ x=10-4 \ x=6$

Ответ: $(6;4)$

Answer 2

$left { {{x+y = 10} atop {x-y = 2}} right. - left { {{x+y = 10} atop {x-y=2}} right. (x + y) - (x - y) = 10 - 2 2y = 8 y = 4 x + (4) = 10 x = 6 ( 6 ; 4 )$