To find out what t + 1 is, we first must find out the value of t.
We know that t + 8 = -12, so all we need to do to solve for t is subtract 8 from both sides.
t + 8 = -12
t + 8 - 8 = -12 - 8
t = -20
So now that we know the value of t, all we need to do to find t + 1 is insert the value of t into the variable and solve.
t + 1 = ?
-20 + 1 = ?
-19
And there we have it.
t + 1 = -19
Hope that helped! =)