-21=y-6

Solution for -21=y-6 equation:

Simplifying
-21 = y + -6

Reorder the terms:
-21 = -6 + y

Solving
-21 = -6 + y

Solving for variable 'y'.

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

Add '-1y' to each side of the equation.
-21 + -1y = -6 + y + -1y

Combine like terms: y + -1y = 0
-21 + -1y = -6 + 0
-21 + -1y = -6

Add '21' to each side of the equation.
-21 + 21 + -1y = -6 + 21

Combine like terms: -21 + 21 = 0
0 + -1y = -6 + 21
-1y = -6 + 21

Combine like terms: -6 + 21 = 15
-1y = 15

Divide each side by '-1'.
y = -15

Simplifying
y = -15