Question

How do i solve 19. c)

Answer 1

n₁ = 8

n₂ = - 3

Explanation:

√(7n + 25) - n = 1

√(7n + 25) = n + 1

[√(7n + 25)]² = (n + 1)²

7n + 25 = n² + 2n + 1

n² + 2n + 1 - 7n - 25 = 0

n² - 5n - 24 = 0

n² + 3n - 8n - 24 = 0

n(n + 3) - 8(n + 3) = 0

(n - 8)(n + 3) = 0

n - 8 = 0 => n₁ = 8

n + 3 = 0 => n₂ = - 3