Question

x-y=5
x-4y=10
cрочно решите дам 40 балов!!1

Answer 1

$\displaystyle\bf\\\left \{ {{x - y = 5} \atop {x - 4y = 10 \: \: | \times ( - 1) }} \right. \\ \displaystyle\bf\\ + \left \{ {{x - y = 5} \atop { - x + 4y = - 10 }} \right. \\ \\ 4y - y = 5 - 10 \\ 3y = - 5 \\ y = - 5 \div 3 \\ y = - 1 \frac{2}{3} \\ \\ x - ( - 1 \frac{2}{3} ) = 5 \\ x + 1 \frac{2}{3} = 5 \\ x = 5 - 1 \frac{2}{3} x = 4 \frac{3}{3} - 1 \frac{2}{3} \\ x = 3 \frac{1}{3}$

Ответ: ( 3 1/3 ; - 1 2/3 )