Question

Упростите выражение (b – 5)(b + 5) (b² + 25) — (b² – 9)² и найдите его значение при b = - 1
3
b=1:3​

Answer 1

(b – 5)(b + 5) (b² + 25) — (b² – 9)²

(b² – 25) (b² + 25) — (b² – 9)² = b^4 – 625 – b^4 + 18b² – 81 = 18b² – 706

1) b = -1

18b² – 706 = 18 · (-1)² - 706 = 18 · 1 - 706 = 18 - 706 = - 688

2) b = 3

18b² – 706 = 18 · (3)² - 706 = 18 · 9 - 706 = 162 - 706 = - 544

3) b = $\frac{1}{3}$

18b² – 706 = 18 · (  $\frac{1}{3}$)² - 706 = 18 · $\frac{1}{9}$ - 706 = 2 - 706 = - 704