Final answer:
The simplified expression equivalent to -9 / √10 is -9√10 / 10.
Step-by-step explanation:
The expression -9 / √10 can be simplified by rationalizing the denominator. To rationalize the denominator, we multiply the numerator and denominator by √10. This eliminates the square root in the denominator. The simplified expression is (-9 * √10) / (√10 * √10). Simplifying further, we get -9√10 / 10.