-1=a+15

Solution for -1=a+15 equation:

Simplifying
-1 = a + 15

Reorder the terms:
-1 = 15 + a

Solving
-1 = 15 + a

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 = 15 + a + -1a

Combine like terms: a + -1a = 0
-1 + -1a = 15 + 0
-1 + -1a = 15

Add '1' to each side of the equation.
-1 + 1 + -1a = 15 + 1

Combine like terms: -1 + 1 = 0
0 + -1a = 15 + 1
-1a = 15 + 1

Combine like terms: 15 + 1 = 16
-1a = 16

Divide each side by '-1'.
a = -16

Simplifying
a = -16