What are the solutions to the equation x(x + 1) = 0? a. x = 0 only b. x = 1 only c. x = 0 or x = 1 d. x = 0 or x = -1

The answer is D: x = 0 or x = -1

Proof:

Solve for x over the real numbers:
x (x + 1) = 0

Split into two equations:
x = 0 or x + 1 = 0

Subtract 1 from both sides:
  x = 0 or x = -1

The answer is the third choice