Question

СРОЧНО! ПОСЛЕДНИЕ БАЛЛЫ ОТДАЮ

Answer 1

Ответ

$1.\\\\\left \{ {{8x-3y-7=0} \atop {3x+y-9=0}} \right. => \left \{ {{8x-3y-7=0} \atop {y=-3x+9}} =>\right. \left \{ {{8x-3(-3x+9)-7=0} \atop {y=-3x+9}} \right. =>\left \{ {{17x-34=0} \atop {y=-3x+9}} \right. =>\left \{ {{x=2} \atop {y=-3x+9}} \right.=>\left \{ {{x=2} \atop {y=3}} \right. \\OTBET: x=2; y=3$

$2.\\\\\left \{ {{15x-11y=25} \atop {5x-4y=10}} \right. => - \left \{ {{15x-11y=25} |:4\atop {5x-4y=10}|:11}\right. =>\left \{ {{x=-2} \atop {15*(-2)-11y=25}} \right. \\=>\left \{ {{x=-2} \atop {y=-5}} \right. 4*(15x-11y)-11*(5x-4y)=4*25-11*10\\5x=-10\\x=-2\\OTBET: x=-2; y=-5$