Me with all of the work for this equation: -8t-23=-15 :

Add 23 to both sides of the equal sign giving you -8t= 8 then divide both sides of the equal sign by -8 which gives you t= -1

Here's the work:

-8t - 23 = -15                    23 + (-15) = 8
     +23    +23
 -8t = 8
 t= -1

1. 8 or -82. 14 or -143. -11, -3, 0, 7, 10