-15,81-9х=21,36

-15,81 - 9х = 21,36-9х = 21,36 + 15,81-9х = 28,179х = -28,17х = - 28,17 : 9х = - 28 17/100 : 9х = - 2817/100 : 9х = - 2817/900х = - 939/300х = - 313/100х = -3,13Ответ: -3,13.