Question

7. Розв'яжіть систему рівнянь
$\frac{15x + 7y}{16} - \frac{3x - y}{4} = - 1 \\ 3x - \frac{10 - y}{6} = 2 - y$
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Answer 1

$\displaystyle\bf\\\left \{ {{ \frac{15x + 7y}{16} - \frac{3x - y}{4} = - 1 \: \: | \times 16 } \atop {3x - \frac{10 - y}{6} = 2 - y \: \: | \times 6 }} \right. \\ \displaystyle\bf\\\left \{ {{15x + 7y - 4(3x - y) = - 16} \atop {18x - (10 - y) + 6y = 12 }} \right. \\ \displaystyle\bf\\\left \{ {{15x + 7y - 12x + 4y = - 16} \atop {18x - 10 + y + 6y = 12 }} \right. \\ \displaystyle\bf\\\left \{ {{3x + 11y = - 16 \: \: | \times ( - 6) } \atop {18x + 7y = 22 }} \right. \\ \displaystyle\bf\\ + \left \{ {{ - 18x - 66y = 96} \atop {18x + 7y = 22 }} \right. \\ \\ 7y - 66y = 96 + 22 \\ - 59y = 118 \\ y = 118 \div ( - 59) \\ y = - 2 \\ \\ 3x + 11 \times ( - 2) = - 16 \\ 3x - 22 = - 16 \\ 3x = - 16 + 22 \\ 3x = 6 \\ x = 6 \div 3 \\ x = 2$

Ответ: ( 2 ; - 2 )