6. Решите уравнение. a) (5x-2)(5x + 2) - (5x-1)² = 4; б) 100x² - 16 = 0.

6. Решите уравнение. а) $$(5x - 2)(5x + 2) - (5x - 1)^2 = 4$$ $$25x^2 - 4 - (25x^2 - 10x + 1) = 4$$ $$25x^2 - 4 - 25x^2 + 10x - 1 = 4$$ $$10x - 5 = 4$$ $$10x = 9$$ $$x = \frac{9}{10} = 0,9$$ б) $$100x^2 - 16 = 0$$ $$100x^2 = 16$$ $$x^2 = \frac{16}{100} = \frac{4}{25}$$ $$x = \pm \sqrt{\frac{4}{25}} = \pm \frac{2}{5} = \pm 0,4$$ **Ответы: а) $$x = 0,9$$; б) $$x = \pm 0,4$$**