Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
variable [ˈvɛərɪəbl] adj (likely to change, mood, quality, weather) изме́нчивый/изме́нчив (able to be changed, temperature, height, speed) переме́нный
n фа́ктор; (MATH) переме́нная f adj
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.
Русский: