First off, we'll convert the mixed fractions to "improper",

The first thing we must do is calculate the circumeference:

now, calculate the angle of arc
360° = 49.612
360° - 66.4° - 180° = x
x = 113.6°
now, to calculate the arc length it would be:
Answer:
x = - 9, x = 6
Step-by-step explanation:
Given
x² + 3x - 54
To find the solutions equate to zero
x² + 3x - 54 = 0 ← in standard form
(x + 9)(x - 6) = 0 ← in factored form
Equate each factor to zero and solve for x
x + 9 = 0 ⇒ x = - 9
x - 6 = 0 ⇒ x = 6