Question

Помогите!!! Решить нужно срочно!!! Даю 70 балов!!!!!!!!!!!!

Answer 1

$\displaystyle\bf\\\left \{ {{3(x - 5) = 8y + 9} \atop {7(x + 2) - 4(y + 5) = 28 }} \right. \\ \displaystyle\bf\\\left \{ {{3x - 15 - 8y = 9} \atop {7x + 14 - 4y - 20 = 28 }} \right. \\ \displaystyle\bf\\\left \{ {{3x - 8y = 24} \atop {7x - 4y = 34 \: \: | \times ( - 2)}} \right. \\ \displaystyle\bf\\ + \left \{ {{3x - 8y = 24} \atop { - 14x + 8y = - 68 }} \right. \\ \\ 3x - 14x = 24 - 68 \\ - 11x = - 44 \\ x = - 44 \div ( - 11) \\ x = 4 \\ \\ 7 \times 4 - 4y = 34 \\ 28 - 4y = 34 \\ 4y = 28 - 34 \\ 4y = - 6 \\ y = - 6 \div 4 \\ y = - 1.5$

Ответ: ( 4 ; - 1,5 )