[latex]3t-7=5t\\ 5t-3t=-7\\ 2t=-7|\cdot3\\ \boxed{6t=-21} [/latex]

[latex]3t-7=5t \ \ \ |\hbox{subtract 3t} \\ -7=5t-3t \\ -7=2t \ \ \ |\hbox{multiply by 3} \\ \boxed{6t=-21}}[/latex]