Решите номер 18 срочно!!!!!!!

a) x² - 5 = 11;

x² = 11 + 5;

x² = 16;

x1 = 4;

x2 = -4;

б) -3x² - 4 = 1.2;

-3x² + 4 = $-15x^{2} + 20 = 6;\\-15x^{2} = 6 - 20\\-15x^{2} = -14\\x1 = -\sqrt{\frac{210}{10} } \\\\x1 = \sqrt{\frac{210}{10} } \\$ | * 5;

в) $-\frac{5}{4}x^{2} = x^{2} | * 4\\-5x^{2} = 4x^{2} \\-5x^{2} - 4x^{2} = 0\\-9x^{2} = 0\\x^{2} = 0\\x = 0$

г) нет решений

д) $\sqrt{3}x^{2} - \sqrt{27} = 0\\\sqrt{3}x^{2} - 3\sqrt{3} = 0 | / \sqrt{3} \\ x^{2} - 3 = 0;\\x^{2} = 3\\x1 = - \sqrt{3} \\x2 = \sqrt{3}$

е) $\sqrt{5}x^{2} - 5x = 0\\ x * (\sqrt{5}x - 5) = 0\\ x = 0; \sqrt{5}x - 5 = 0;\\ x1 = 0, x2 = \sqrt{5};$

фух, удачи