Question

Помогите пожалуйста решить систему! Фигурная скобка 4x-y=1
5x+y=8.

Answer 1

$\left \{ {{4x-y=1} \atop {5x+y=8}} \right.\; \oplus \; \left \{ {{9x=9} \atop {y=8-5x}} \right.\; \; \left \{ {{x=1} \atop {y=3}} \right.\; \; \to \; \; (1,3)$

Answer 2

Метод подстановки:

$\left \{ {{4x-y=1,} \atop {5x+y=8;}}\right.\\\\\left \{ {{y=4x-1,} \atop {5x+y=8;}}\right. \\\\\left \{ {{y=4x-1,} \atop {5x+4x-1=8;}}\right. \\\\\left \{ {{y=4x-1,} \atop {9x=8+1;}}\right. \\\\\left \{ {{y=3,} \atop {x=1.}}\right. \\ \\ OTBET:(1;3)$

Метод сложения:

$+\left \{ {{4x-y=1,} \atop {5x+y=8;}} \right. \\ \\ \left \{ {{4x-y+5x+y=1+8,} \atop {5x+y=8;}} \right. \\ \\ \left \{ {{9x=9,} \atop {y=8-5x;}} \right. \\ \\ \left \{ {{x=1,} \atop {y=3.}} \right. \\ \\ OTBET:(1;3)$