133. Решите уравнения:
а) $$49-16x^2 = 0$$
$$16x^2 = 49$$
$$x^2 = \frac{49}{16}$$
$$x = \pm \sqrt{\frac{49}{16}}$$
$$x = \pm \frac{7}{4}$$
Ответ: $$x_1 = 1.75, x_2 = -1.75$$
б) $$25x^2 - 9 = 0$$
$$25x^2 = 9$$
$$x^2 = \frac{9}{25}$$
$$x = \pm \sqrt{\frac{9}{25}}$$
$$x = \pm \frac{3}{5}$$
Ответ: $$x_1 = 0.6, x_2 = -0.6$$
в) $$-1 + 4x^2 = 0$$
$$4x^2 = 1$$
$$x^2 = \frac{1}{4}$$
$$x = \pm \sqrt{\frac{1}{4}}$$
$$x = \pm \frac{1}{2}$$
Ответ: $$x_1 = 0.5, x_2 = -0.5$$
г) $$-8 + 128x^2 = 0$$
$$128x^2 = 8$$
$$x^2 = \frac{8}{128}$$
$$x^2 = \frac{1}{16}$$
$$x = \pm \sqrt{\frac{1}{16}}$$
$$x = \pm \frac{1}{4}$$
Ответ: $$x_1 = 0.25, x_2 = -0.25$$
134. Решите уравнения:
а) $$(x-3)^2 + (3x+1)^2 = 20$$
$$x^2 - 6x + 9 + 9x^2 + 6x + 1 = 20$$
$$10x^2 + 10 = 20$$
$$10x^2 = 10$$
$$x^2 = 1$$
$$x = \pm 1$$
Ответ: $$x_1 = 1, x_2 = -1$$
б) $$(5x-2)^2 + (x+10)^2 = 104$$
$$25x^2 - 20x + 4 + x^2 + 20x + 100 = 104$$
$$26x^2 + 104 = 104$$
$$26x^2 = 0$$
$$x^2 = 0$$
$$x = 0$$
Ответ: $$x = 0$$
в) $$(6-x)^2 = (3x-2)^2 - 40$$
$$36 - 12x + x^2 = 9x^2 - 12x + 4 - 40$$
$$36 + x^2 = 9x^2 - 36$$
$$8x^2 = 72$$
$$x^2 = 9$$
$$x = \pm 3$$
Ответ: $$x_1 = 3, x_2 = -3$$
г) $$(10-3x)^2 = (5x-6)^2$$
$$100 - 60x + 9x^2 = 25x^2 - 60x + 36$$
$$100 + 9x^2 = 25x^2 + 36$$
$$16x^2 = 64$$
$$x^2 = 4$$
$$x = \pm 2$$
Ответ: $$x_1 = 2, x_2 = -2$$