á) 5 \(\cdot\) (δ-7) = 3 \(\cdot\) (δ-4) - 27;

Решение:

1. \( 5(\delta - 7) = 3(\delta - 4) - 27 \)
2. \( 5\delta - 35 = 3\delta - 12 - 27 \)
3. \( 5\delta - 35 = 3\delta - 39 \)
4. \( 5\delta - 3\delta = -39 + 35 \)
5. \( 2\delta = -4 \)
6. \( \delta = \frac{-4}{2} \)
7. \( \delta = -2 \)

Ответ: \( \delta = -2 \).