При m=-1:[tex] - \frac{7}{8} \cdot (-1) - 1 {}^{3 } = \frac{7}{8} - 1 = \frac{7-8}{8} = -\frac{1}{8} [/tex]
При [tex]m = \frac{4}{7} [/tex]:[tex] - \frac{7}{8} \cdot \frac{4}{7} - 1 {}^{3 } = -\frac{1}{2} - 1 = -\frac{3}{2} [/tex]
При m=-1:
[tex] - \frac{7}{8} \cdot (-1) - 1 {}^{3 } = \frac{7}{8} - 1 = \frac{7-8}{8} = -\frac{1}{8} [/tex]
При [tex]m = \frac{4}{7} [/tex]:
[tex] - \frac{7}{8} \cdot \frac{4}{7} - 1 {}^{3 } = -\frac{1}{2} - 1 = -\frac{3}{2} [/tex]