0=(t-20)+(t-400)

Solution for 0=(t-20)+(t-400) equation:

Simplifying
0 = (t + -20) + (t + -400)

Reorder the terms:
0 = (-20 + t) + (t + -400)

Remove parenthesis around (-20 + t)
0 = -20 + t + (t + -400)

Reorder the terms:
0 = -20 + t + (-400 + t)

Remove parenthesis around (-400 + t)
0 = -20 + t + -400 + t

Reorder the terms:
0 = -20 + -400 + t + t

Combine like terms: -20 + -400 = -420
0 = -420 + t + t

Combine like terms: t + t = 2t
0 = -420 + 2t

Solving
0 = -420 + 2t

Solving for variable 't'.

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

Add '-2t' to each side of the equation.
0 + -2t = -420 + 2t + -2t
Remove the zero:
-2t = -420 + 2t + -2t

Combine like terms: 2t + -2t = 0
-2t = -420 + 0
-2t = -420

Divide each side by '-2'.
t = 210

Simplifying
t = 210