Question

розв'яжіть систему рівнянь способом підстановки у=х-3,5х+2у=29

Answer 1

$\displaystyle\bf\\\left \{ {{y=x-3,5} \atop {x+2y=29}} \right.\\\\\\\left \{ {{y=x-3,5} \atop {x+2\cdot(x-3,5)=29}} \right. \\\\\\\left \{ {{y=x-3,5} \atop {x+2x-7=29}} \right. \\\\\\\left \{ {{y=x-3,5} \atop {3x=29+7}} \right. \\\\\\\left \{ {{y=x-3,5} \atop {3x=36}} \right. \\\\\\\left \{ {{x=12} \atop {y=12-3,5}} \right. \\\\\\\left \{ {{x=12} \atop {y=8,5}} \right. \\\\\\Otvet: \Big (12 \ ; \ 8,5\Big)$