Solve for x if 1 + x + x^2 + x^3 + x^4 + ... = 15.
Solve for x: 1/(1 - x) = 15
Take the reciprocal of both sides: 1 - x = 1/15
Subtract 1 from both sides: -x = -14/15
Multiply both sides by -1: x = 14/15