Expand the brackets
—That’ll be 3t + 9 + 15 + 10t - 76 = 0
Then we rearrange
3t + 10t = 13t
15+9-76 = - 52
Therefore , it’ll be 13t - 52 = 0
Take “-52” to the other side then it’ll turn to “ +52”
13t = 52
Divide both sides by 13
13t/13 = 52/13
T = 4
Simple