Question

Найти неизвестные х+у=23 и 2х+3у=61

Answer 1

$displaystyle tt left { {{x+y=23} atop {2x+3y=61}} right. to left { {{x=23-y} atop {2x+3y=61}} right. \\displaystyle tt 2(23-y)+3y=61\displaystyle tt 46-2y+3y=61\displaystyle tt y=61-46\displaystyle tt bold{y=15}\\displaystyle tt x=23-15\displaystyle tt bold{x=8}\\displaystyle tt (x; : y)=(8; : 15)$

Ответ: $displaystyle tt (x; : y)=(8; : 15)$