Question

2x + 11y = 15;
- 10x + 11y = - 9
Способом додавання

Answer 1

$\displaystyle\bf\\\left \{ {{2x+11y=15} \atop {-10x+11y=-9} \ |\cdot(-1)} \right. \\\\\\+\left \{ {{2x+11y=15} \atop {10x-11y=9} } \right. \\----------\\12x=24\\\\x=24:12=2\\\\11y=15-2x=15-2\cdot 2=15-4=11\\\\y=11:11=1\\\\\\Otvet \ : \ (2 \ ; \ 1)$