Respuesta :

The difference between the solution to the equation x² = a is 30.
x² = a
x = √a or x = -√a.

The difference between the solutions satisfies the condition
√a - (-√a) = 30
2√a = 30
√a = 15
a = 15² = 225

Check the answer.
When x = +√a,
x² = (√a)² = a   Correct
When x = -√a,
x² = (-√a)² = a  Correct

Answer:  a = 225, and the answer checks out to be correct.