Question

Решите систему уравнений способом подстановки.
2х + у = 2,
4х - 3 к = 24.


3х + 2 у= 6,
2х - у= 1.

Answer 1

1)

$\left \{{{2x + y = 2} \atop {4x -3y = 24}} \right\\\left \{ {{y=2 - 2x} \atop {4x -3y = 24}} \right. \\4 x - 3 * (2 - 2x) = 24\\4x - 6 + 6x = 24\\4x + 6x = 24 + 6\\10x = 30\\x = \frac{30}{10} = 3\\y = 2 - 2 * 3 = 2 - 6 = -4$

2)

$\left \{ {{3x + 2y = 6} \atop {2x - y = 1}} \right. \\\left \{ {{3x + 2y = 6} \atop {y = -1 + 2x}} \right. \\\\3x + 2 * (-1 + 2x) = 6\\3x - 2 + 4x = 6\\7x = 6 + 2\\7x = 8\\x = \frac{8}{7}\\y = -1 + 2 * \frac{8}{7} = -1 + \frac{16}{7} = \frac{-7 + 16}{7} = \frac{9}{7}$