Question

The real values of t satisfying the equation (3t – 9)3 + (9t – 3)3 = (9t + 3t – 12)3 are

(A) –1

(B) 1

(C) 1/2

(D) 2

Answer 1

Correct option (B) (C) (D)

Explanation:

Let 3t = a

(a – 9)3 + (a2 – 3)3 = [(a2 – 3) + (a – 9)]3

3(a2 – 3)(a – 9)[a2 – 3 + a – 9] = 0

a = ±3, ± √3 , –4, 9

so t = 1, 1/2, 2