5. Решите уравнение: a) $$(4x - 3)(4x + 3) - (4x - 1)^2 = 3x$$; б) $$16c^2 - 49 = 0$$.

a) $$(16x^2 - 9) - (16x^2 - 8x + 1) = 3x 16x^2 - 9 - 16x^2 + 8x - 1 = 3x 8x - 10 = 3x 5x = 10 x = 2$$ б) $$16c^2 = 49 c^2 = \frac{49}{16} c = \pm\frac{7}{4}$$