Question 264276
15 less than the square of a number x^-15
is the same as twice the number = 2x

x^-15 = 2x
x^-2x-15
(x-5)(x+3)
x = 5 or x =-3

check:
1)5^-15 = 2(5)
  25-15 = 10
  10 = 10
or
2)-3^-15 = 2(-3)
  9-15 = -6
  -6 = -6