Question

помогите пожалуйста срочно!!​

Answer 1

1)

$\displaystyle\bf\\\left \{ {{5x + 2y = 11} \atop {2x - y = 8 }} \right. \\ \displaystyle\bf\\\left \{ {{5x + 2(2x - 8) = 11} \atop {y = 2x - 8 }} \right. \\ \\ 5x + 4x - 16 = 11 \\ 9x = 11 + 16 \\ 9x = 27 \\ x = 27 \div 9 \\ x = 3 \\ \\ y = 2 \times 3 - 8 \\ y = 6 - 8 \\ y = - 2$

Ответ: ( 3 ; - 2 )

2)

$\displaystyle\bf\\ + \left \{ {{2x - 3y = - 14} \atop {7x + 3y = - 22 }} \right. \\ \\ 2x + 7x = - 14 - 22 \\ 9x = - 36 \\ x = - 36 \div 9 \\ x = - 4 \\ \\ 7 \times ( - 4) + 3y = - 22 \\ - 28 + 3y = - 22 \\ 3y = - 22 + 28 \\3 y = 6 \\ y = 6 \div 3 \\ y = 2$

Ответ: ( - 4 ; 2 )

3)

$\displaystyle\bf\\\left \{ {{3(5 - 4x) - 2(5y - 7) = 23} \atop {4(3y - 2) - (2 + 3x) = 32 }} \right. \\ \displaystyle\bf\\\left \{ {{15 - 12x - 10y + 14 = 23} \atop {12y - 8 - 2 - 3x = 32 }} \right. \\ \displaystyle\bf\\\left \{ {{ - 12x - 10y = - 6} \atop { - 3x + 12y = 42 \: \: | \times ( - 4) }} \right. \\ \displaystyle\bf\\ + \left \{ {{ - 12x - 10y = - 6} \atop { 12x - 48y = - 168 }} \right. \\ \\ - 10y - 48y = - 168 - 6 \\ - 58y = - 174 \\ y = - 174 \div ( - 58) \\ y = 3 \\ \\ - 3x + 12 \times 3 = 42 \\ - 3x + 36 = 42 \\ 3x = 36 - 42 \\ 3x = - 6 \\ x = - 6 \div 3 \\ x = - 2$

Ответ: ( - 2 ; 3 )