Question

мне нужен ответ .как это решит я ничего не понял помогите

Answer 1

$\displaystyle\bf\\\\\left \{ {{\dfrac{6x}{7} +\dfrac{5y}{21} =5} \atop {\dfrac{9x}{4}-\dfrac{y}{12} =11}} \right. \\\\\\\displaystyle\bf\\\\\left \{ {{\dfrac{6x}{7} \cdot 21+\dfrac{5y}{21} \cdot 21=5\cdot 21} \atop {\dfrac{9x}{4}\cdot 12-\dfrac{y}{12}\cdot 12 =11\cdot 12}} \right. \\\\\\\displaystyle\bf\\\\\left \{ {6x\cdot 3+5y=105} \atop {9x\cdot 3-y=132}} \right. \\\\\\\displaystyle\bf\\\\\left \{ {18x+5y=105} \atop {27x-y=132}} \right.$

$\displaystyle\bf\\\\+\left \{ {18x+5y=105} \atop {135x-5y=660}} \right.\\----------\\\displaystyle\bf\\153x=765\\\displaystyle\bf\\x=5\\\displaystyle\bf\\y=27x-132=27\cdot 5-132=135-132=3\\\displaystyle\bf\\Otvet:\boxed{(5 \ ; \ 3)}$