If the median of the following data is 11, then find the value of K: 3, 21, 10, 7, 6, 9, (K + 6), 15, 20

If x + (1/x) = 3, then the value of x³ + (1/x³) is :

Find the value of x, if 3⁴ × 3ˣ = 3⁸:

If (a² − 1)/a = 2, then the value of (a⁶ − 1)/a³ is:

If x³ = (9³ × 6³) / 8, x > 0, then what is the value of x?

If 2^(x−1) + 2^(x+1) = 1280, then the value of x²+9x is