Thinking this is to solve for t:
(7t - 2) - (-3 + 1) = -3(1 - 3t)
7t - 2 - (1 - 3) = -3*1 + 3*3t
7t - 2 -(-2) = -3 + 9t
7t -2 + 2 = -3 + 9t
7t + 0 = -3 + 9t
7t = -3 + 9t
7t - 9t = -3
-2t = -3 Divide by -2 to get t.
t = -3/-2
t = 3/2 or 1.5
Hope this explains it.