Concept:Use principal values of inverse trigonometric functions and simplify to find x.Explanation:Since tan4π=1, we get sin−1(1)=2π.The given equation becomes:2π−sin−1(x3)=6πSo,sin−1(x3)=2π−6π=3πTaking sine on both sides:x3=sin3π=23Squaring both sides:x3=43⇒x=4Now check which quadratic equation has x=4 as a root.For x=4:x2−x−12=16−4−12=0Hence, x=4 satisfies x2−x−12=0.Answer:Option B: x2−x−12=0