7 * (1/7)^2 - 8 * (1/7)

Решение:

1. \[ 7 \times \left(\frac{1}{7}\right)^2 - 8 \times \frac{1}{7} = 7 \times \frac{1}{49} - \frac{8}{7} \]
2. \[ \frac{7}{49} - \frac{8}{7} = \frac{1}{7} - \frac{8}{7} = \frac{1-8}{7} = -\frac{7}{7} = -1 \]

Ответ: -1