(y - 4) ^ 2 - (6 + y)(1 - 6) при y = - 7/8

Подставляем y = -7/8:

(-7/8 - 4)^2 - (6 + (-7/8))(1 - 6) = (-(39/8))^2 - (6 - 7/8)(-5) = (1521/64) - (53/8)(-5) = 1521/64 - 265/8 = 2296/64 - 2120/64 = 176/64 = 11/4.

Ответ: 11/4.