Question

розв'язати систему рівнянь 2х+3у=7 -5х+2у=11​ метод підстановки

Answer 1

$\displaystyle\bf\\\left \{ {{2x + 3y = 7} \atop { - 5x + 2y = 11 }} \right. \\ \displaystyle\bf\\\left \{ {{2x = 7 - 3y \: \: | \div 2 } \atop { - 5x + 2y = 11 }} \right. \\ \displaystyle\bf\\\left \{ {{x = 3.5 - 1.5y} \atop { - 5(3.5 - 1.5y) + 2y = 11 }} \right. \\ \\ - 17.5 + 7.5y + 2y = 11 \\ 9.5y = 11 + 17.5 \\ 9.5y = 28.5 \\ y = 28.5 \div 9.5 \\ y = 3 \\ \\ x = 3.5 - 1.5 \times 3 \\ x = 3.5 - 4.5 \\ x = - 1$

Ответ: ( - 1 ; 3 )