Для нахождения координат середины отрезка используем формулы:
$$M_x = \frac{A_x + B_x}{2}$$
$$M_y = \frac{A_y + B_y}{2}$$
A(2; -3), B(-3; 1)
$$M_x = \frac{2 + (-3)}{2} = \frac{-1}{2} = -0.5$$
$$M_y = \frac{-3 + 1}{2} = \frac{-2}{2} = -1$$
M(-0.5; -1)
A(0; 1), B(4; 7)
$$M_x = \frac{0 + 4}{2} = \frac{4}{2} = 2$$
$$M_y = \frac{1 + 7}{2} = \frac{8}{2} = 4$$
M(2; 4)
A(0; 0), B(-3; 7)
$$M_x = \frac{0 + (-3)}{2} = \frac{-3}{2} = -1.5$$
$$M_y = \frac{0 + 7}{2} = \frac{7}{2} = 3.5$$
M(-1.5; 3.5)
A(c; d), M(-3; -2)
Используем формулы в обратном порядке:
$$M_x = \frac{A_x + B_x}{2} \Rightarrow A_x + B_x = 2M_x \Rightarrow B_x = 2M_x - A_x$$
$$B_x = 2 \cdot (-3) - c = -6 - c$$
$$M_y = \frac{A_y + B_y}{2} \Rightarrow A_y + B_y = 2M_y \Rightarrow B_y = 2M_y - A_y$$
$$B_y = 2 \cdot (-2) - d = -4 - d$$
B(-6 - c; -4 - d)
A(3; 5), M(3; -5)
$$B_x = 2 \cdot 3 - 3 = 6 - 3 = 3$$
$$B_y = 2 \cdot (-5) - 5 = -10 - 5 = -15$$
B(3; -15)
A(3t + 5; 7), B(t + 7; -7)
$$M_x = \frac{(3t + 5) + (t + 7)}{2} = \frac{4t + 12}{2} = 2t + 6$$
$$M_y = \frac{7 + (-7)}{2} = \frac{0}{2} = 0$$
M(2t + 6; 0)
A(1; 3), M(0; 0)
$$B_x = 2 \cdot 0 - 1 = -1$$
$$B_y = 2 \cdot 0 - 3 = -3$$
B(-1; -3)
Заполненная таблица:
| (2; -3), (-3; 1), (-0.5; -1) | (0; 1), (4; 7), (2; 4) | (0; 0), (-3; 7), (-1.5; 3.5) | (c; d), (-6-c; -4-d), (-3; -2) | (3; 5), (3; -15), (3; -5) | (3t + 5; 7), (t + 7; -7), (2t+6; 0) | (1; 3), (-1; -3), (0; 0) | |
| A | (2; -3) | (0; 1) | (0; 0) | (c; d) | (3; 5) | (3t + 5; 7) | (1; 3) |
| B | (-3; 1) | (4; 7) | (-3; 7) | (-6-c; -4-d) | (3; -15) | (t + 7; -7) | (-1; -3) |
| M | (-0.5; -1) | (2; 4) | (-1.5; 3.5) | (-3; -2) | (3; -5) | (2t+6; 0) | (0; 0) |
Ответ: см. таблицу выше