-1=a+b+c

Solution for -1=a+b+c equation:

Simplifying
-1 = a + b + c

Solving
-1 = a + b + c

Solving for variable 'a'.

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

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

Reorder the terms:
-1 + -1a = a + -1a + b + c

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

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

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

Reorder the terms:
-1a = 1 + b + c

Divide each side by '-1'.
a = -1 + -1b + -1c

Simplifying
a = -1 + -1b + -1c