Question

СРОЧНО!!!
ПОМОГИТЕ ПОЖАЛУЙСТА

Answer 1

$1)+\left \{ {{2x+5xy=14} \atop {y-5xy=-9}} \right.\\--------\\2x+y=5\\\\y=5-2x\\\\\left \{ {{2x+5x*(5-2x)=14} \atop {y=5-2x}} \right.\\\\\left \{ {{2x+25x-10x^{2}-14=0 } \atop {y=5-2x}} \right. \\\\\left \{ {{10x^{2}-27x+14=0 } \atop {y=5-2x}} \right.\\\\10x^{2}-27x+14=0\\\\D=(-27)^{2}-4*10*14=729-560=169=13^{2}\\\\x_{1}=\frac{27-13}{20}=0,7\\\\x_{2}=\frac{27+13}{20}=2\\\\y_{1}= 5-2*0,7=3,6\\\\y_{2}=5-2*2=1\\\\Otvet:\boxed{(0,7;3,6),(2;1)}$

2) Сделаем замену :

$xy=m,\frac{x}{y}=n\\\\\left \{ {{m-n=6}|*2 \atop {3m+2n=28}} \right.\\\\+\left \{ {{2m-2n=12} \atop {3m+2n=28}} \right.\\ -------\\5m=40\\\\m=8\\\\n=m-6=8-6=2\\\\\left \{ {{xy=8} \atop {\frac{x}{y}=2 }} \right. \\\\\left \{ {{x=2y} \atop {2y*y=8}} \right.\\\\\left \{ {{x=2y} \atop {y^{2}=4 }} \right.$

$1)\left \{ {{x=2y} \atop {y_{1}=-2 }} \right.\\\\\left \{ {{x_{1}=2*(-2)=-4 } \atop {y_{1}=-2}} \right.\\\\2)\left \{ {{x=2y} \atop {y_{2}=2}} \right.\\\\\left \{ {{x_{2}=2*2=4 } \atop {y_{2}=2 }} \right. \\\\Otvet:\boxed{(-4;-2),(4;2)}$