42=8-(t-20)

Solution for 42=8-(t-20) equation:

Simplifying
42 = 8 + -1(t + -20)

Reorder the terms:
42 = 8 + -1(-20 + t)
42 = 8 + (-20 * -1 + t * -1)
42 = 8 + (20 + -1t)

Combine like terms: 8 + 20 = 28
42 = 28 + -1t

Solving
42 = 28 + -1t

Solving for variable 't'.

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

Add 't' to each side of the equation.
42 + t = 28 + -1t + t

Combine like terms: -1t + t = 0
42 + t = 28 + 0
42 + t = 28

Add '-42' to each side of the equation.
42 + -42 + t = 28 + -42

Combine like terms: 42 + -42 = 0
0 + t = 28 + -42
t = 28 + -42

Combine like terms: 28 + -42 = -14
t = -14

Simplifying
t = -14