Question

Using the equation x squared minus c equals 0 , what value of c has 9 and -9 as solutions.

Answer 1

9514 1404 393

Answer:

  c = 81

Step-by-step explanation:

The equation x² -c = 0 can be factored as ...

  (x -√c)(x +√c) = 0

which has roots ±√c.

The roots are given as ±9, so we have ...

  ±9 = ±√c

  c = (±9)² = 81

The value c = 81 makes the equation have ±9 as solutions.