Question

розв'яжіть систему рівнянь:
Даю 50 БАЛОВ ​

Answer 1

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Answer 2

$\displaystyle\bf\\\left \{ {{x - 4y = 2} \atop {xy + 2y = 8 }} \right. \\ \displaystyle\bf\\\left \{ {{x = 4y + 2} \atop {y(4y + 2) + 2y = 8 }} \right. \\ \\ 4 {y}^{2} + 2y + 2y= 8 \\ 4 {y}^{2} + 4y - 8 = 0 \\ {y}^{2} + y - 2 = 0 \\ a =1 \\ b = 1 \\ c = - 2\\ D = {b}^{2} - 4ac = {1}^{2} - 4 \times1 \times ( - 2) = 1 + 8 = 9\\ y_{1} = \frac{ - 1 - 3}{2 \times 1} = - \frac{4}{2} = - 2 \\ y_{2} = \frac{ - 1 + 3}{2 \times 1} = \frac{2}{2} = 1 \\ \\ x_{1} = 4 \times ( - 2) + 2 = - 8 + 2 = - 6 \\ x_{2} = 4 \times 1 + 2 = 4 + 2 = 6$

Ответ: ( - 6 ; - 2 ) и ( 6 ; 1 )