Question

БУДЬ ЛАСКА СРОЧНО ДОПОМОЖІТЬ!​

Answer 1

a)

$\displaystyle\bf\\\left \{ {{7x - 3y = - 5 \: \: | \times 4} \atop {3x + 4y = - 18 \: \: | \times 3 }} \right. \\ \displaystyle\bf\\ + \left \{ {{28x - 12y = - 20} \atop {9x + 12y = - 54 }} \right. \\ \\ 28x + 9x = - 20 - 54 \\ 37x = - 74 \\ x = - 74 \div 37 \\ x = - 2 \\ \\ 3 \times ( - 2) + 4y = - 18 \\ - 6 + 4y = - 18 \\ 4y = - 18 + 6 \\ 4y = - 12 \\ y = - 12 \div 4 \\ y = - 3$

Ответ: ( - 2 ; - 3 )

б)

$\displaystyle\bf\\\left \{ {{ \frac{x + 3}{4} - \frac{y - 2}{6} = 1 \: \: | \times 12 } \atop { \frac{x - 1}{8} + \frac{y + 1}{6} = 2 \: \: | \times 24 }} \right. \\ \displaystyle\bf\\\left \{ {{3(x + 3) - 2(y - 2) = 12} \atop {3(x - 1) + 4(y + 1) = 48 }} \right. \\ \displaystyle\bf\\\left \{ {{3x + 9 - 2y + 4 = 12} \atop {3x - 3 + 4y + 4 = 48 }} \right. \\ \displaystyle\bf\\\left \{ {{3x - 2y = - 1 \: \: | \times 2} \atop {3x + 4y = 47 }} \right. \\ \displaystyle\bf\\ + \left \{ {{6x - 4y = - 2} \atop {3x + 4y = 47 }} \right. \\ \\ 6x + 3x = 47 - 2 \\ 9x = 45 \\ x = 45 \div 9 \\ x = 5 \\ \\ 3 \times 5 + 4y = 47 \\ 15 + 4y = 47 \\ 4y = 47 - 15 \\ 4y = 32 \\ y = 32 \div 4 \\ y = 8$

Ответ: ( 5 ; 8 )