Răspuns: 9
(7⁴ - 7³) : (7² - 7) - 2³ × 5 =
7³ × (7⁴⁻³ - 7³⁻³) : 7 × (7²⁻¹ - 7¹⁻¹) - 8 × 5 =
[7³ × (7¹ - 7⁰)] : [7 × (7¹ - 7⁰)] - 40 =
[7³ × (7 -1)] : [7 × (7 - 1)] - 40 =
(7³ × 6) : (7 × 6) - 40 =
(343 × 6) : 42 - 40 = 2058 : 42 =
49 - 40 = 9