[3t+6]+9=30

Solution for [3t+6]+9=30 equation:

Simplifying
[3t + 6] + 9 = 30

Reorder the terms:
[6 + 3t] + 9 = 30

Remove brackets around [6 + 3t]
6 + 3t + 9 = 30

Reorder the terms:
6 + 9 + 3t = 30

Combine like terms: 6 + 9 = 15
15 + 3t = 30

Solving
15 + 3t = 30

Solving for variable 't'.

Move all terms containing t to the left, all other terms to the right.

Add '-15' to each side of the equation.
15 + -15 + 3t = 30 + -15

Combine like terms: 15 + -15 = 0
0 + 3t = 30 + -15
3t = 30 + -15

Combine like terms: 30 + -15 = 15
3t = 15

Divide each side by '3'.
t = 5

Simplifying
t = 5