Answer:
Infinity
Explanation:
Any integer substituted for t would make the equation true.
If you solve the equation for t, you get this:
18-15t=12+6-15t
15t + 15t = 12 + 6 - 18
0t = 0 or 0 = 0
You can test this by put any integer in for t
t =0 18 - 0 = 12 + 6 +0
18 = 18
t = - 1 18 + 15 = 12 + 6 + 15
33 = 33
t = 1 18 - 1 = 12 + 6 - 1
17 = 17
etc