Представить в виде произведения двучлен с2-0,49= 16-k2= 400-m2= t2-225= 1.69-b2=...

Решите задачу:

$(c {}^{2} - 0.49) = (c - 0.7)(c + 0.7) \\ 16 - k {}^{2} = (4 - k)(4 + k) \\ 400 - m {}^{2} = (20 - m)(20 + m) \\ t {}^{2} - 225 = (t - 15)(t + 15) \\ 1.69 - b {}^{2} = (1.3 - b)(1.3 + b) \\ y {}^{2} - \frac{16}{81} = (y - \frac{4}{9} )(y + \frac{4}{9} ) \\ 25x {}^{2} - 4 = (5x - 2)(5x + 2) \\ \frac{25}{36} - 64y {}^{2} = ( \frac{5}{6} - 8y)( \frac{5}{ 6} + 8y)$