Question

помогите пожалуйста по математике ​

Answer 1

Ответ:

$1)\left \{ {{0,2x+15y=9,8} \atop {0,75x-10y=-3}} \right.\\\left \{ {{0,2x+15y=9,8} \atop {x=-4+\frac{40}{3} y}} \right.\\0,2(-4+\frac{40}{3}y)+15y=9,8\\y=\frac{3}{5} \\x=-4+\frac{40}{3}*\frac{3}{5}\\ x=4\\(x,y)=(4,\frac{3}{5} )\\\left \{ {{0,2*4+15*\frac{3}{5}=9,8 } \atop {0,75*4-10*\frac{3}{5}=-3 }} \right.\\\left \{ {{\frac{49}{5}=\frac{49}{5} } \atop {-3=-3}} \right. \\(x,y)=(4,\frac{3}{5} )$

$2)\left \{ {{0,3x-0,5y=0\\} \atop {0,1x+2y=6,5}} \right.\\\left \{ {{x=y*\frac{5}{3} } \atop {0,1x+2y=6,5}} \right. \\0,1y*\frac{5}{3}+2y=6,5\\y=3\\x=3*\frac{5}{3} \\x=5\\(x,y)=(5,3)\\\left \{ {{0,3*5-0,5*3=0} \atop {0,1*5+2*3=6,5}} \right. \\\left \{ {{0=0} \atop {\frac{13}{2}= }} \right.\frac{13}{2} \\(x,y)=(5,3)$