Question

методом сложения. прошу...​

Answer 1

Ответ: ( -2 ; 3 )

Объяснение:

$\left  \{ \begin {array}{l}  \dfrac{3-x}{5}+ \cfrac{5+y}{4}  =3~~ \big | \cdot 20 \\\\\\ \dfrac{8+x}{3}  - \dfrac{y-1}{2} = 1 ~~  \big |\cdot 6   \end{array}\right. \Leftrightarrow \left  \{ \begin {array}{l} 4(3-x) + 5(5+y) = 60 \\\\  2(x+8)-3(y-1) = 6  \end{array} \right. \Leftrightarrow \\\\\\ \Leftrightarrow \left  \{ \begin {array}{l}  12- 4x + 25 +5y = 60 \\\\ 2x + 16 -3y +3 = 6    \end{array} \right.  \Leftrightarrow \left  \{ \begin {array}{l} 5y  -  4x   = 23 \\\\ 2x -3y = -13  \end{array} \right. \Leftrightarrow \\\\\\\   \Leftrightarrow \left  \{ \begin {array}{l} 5y  -  4x   = 23 \\\\ 2x -3y = -13~~ \big |\cdot 2  \end{array} \right.   \Leftrightarrow \oplus \left  \{ \begin {array}{l} 5y  -  4x   = 23 \\\\ 4x -6y = -26   \end{array} \right.  \\\\\\ -6y+5y+4x -4x = 23- 26  \\\\ -y = -3 \\\\ y =3  \\\\ x= (3y -13 ):2 =- 2$