Question

Розв'яжіть способом підстановки систему рівнянь:
( x-5y = 8,
(x+2y = 15;​

Answer 1

$\displaystyle\bf\\\left \{ {{x-5y=8} \atop {x+2y=15}} \right. \\\\\\\left \{ {{x=5y+8} \atop {5y+8+2y=15}} \right.\\\\\\\left \{ {{x=5y+8} \atop {5y+2y=15-8}} \right.\\\\\\\left \{ {{x=5y+8} \atop {7y=7}} \right.\\\\\\\left \{ {{x=5y+8} \atop {y=1}} \right.\\\\\\\left \{ {{x=5\cdot 1+8} \atop {y=1}} \right.\\\\\\\left \{ {{x=13} \atop {y=1}} \right. \\\\\\Otvet \ : \ (13 \ ; \ 1)$