CREATE TABLE table_2112766_1 (broadcast_date VARCHAR, viewers__in_millions_ VARCHAR)

what is all the broadcast date when viewers were 8.4 millions
SELECT COUNT(broadcast_date) FROM table_2112766_1 WHERE viewers__in_millions_ = "8.4"
SELECT COUNT("broadcast_date") FROM "table_2112766_1" WHERE "8.4" = "viewers__in_millions_"