How do you factor 49t^2+36-84t

This is a perfect square,
49t^2+36-84t = (7t-6)^2

49t ^2 -84t + 36

USE FORMULA a^2 -2ab +b^2 = ( a-b)^2

ANSWER ( 7t -6)^2

OR

49t^2 -42t -42t +36

7t ( 7t - 6) - 6( 7t -6)
( 7t - 6) ( 7t - 6) ANSWER

(7t-6)^2