2+(a-1)=-1

Solution for 2+(a-1)=-1 equation:

Simplifying
2 + (a + -1) = -1

Reorder the terms:
2 + (-1 + a) = -1

Remove parenthesis around (-1 + a)
2 + -1 + a = -1

Combine like terms: 2 + -1 = 1
1 + a = -1

Solving
1 + a = -1

Solving for variable 'a'.

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

Add '-1' to each side of the equation.
1 + -1 + a = -1 + -1

Combine like terms: 1 + -1 = 0
0 + a = -1 + -1
a = -1 + -1

Combine like terms: -1 + -1 = -2
a = -2

Simplifying
a = -2