Question

Решите пж по алгебре!)))

Answer 1

$(\frac{1}{5}c- \frac{3}{13}d)(\frac{1}{5}c+\frac{3}{13}d)= (\frac{1}{5}c)^{2}-(\frac{3}{13}d)^{2} =\frac{1}{25}c^{2}-\frac{9}{169}d^{2}$