(t+10.5)+2t=90

Solution for (t+10.5)+2t=90 equation:

Simplifying
(t + 10.5) + 2t = 90

Reorder the terms:
(10.5 + t) + 2t = 90

Remove parenthesis around (10.5 + t)
10.5 + t + 2t = 90

Combine like terms: t + 2t = 3t
10.5 + 3t = 90

Solving
10.5 + 3t = 90

Solving for variable 't'.

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

Add '-10.5' to each side of the equation.
10.5 + -10.5 + 3t = 90 + -10.5

Combine like terms: 10.5 + -10.5 = 0.0
0.0 + 3t = 90 + -10.5
3t = 90 + -10.5

Combine like terms: 90 + -10.5 = 79.5
3t = 79.5

Divide each side by '3'.
t = 26.5

Simplifying
t = 26.5