-42=21y

Solution for -42=21y equation:

Simplifying
-42 = 21y

Solving
-42 = 21y

Solving for variable 'y'.

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

Add '-21y' to each side of the equation.
-42 + -21y = 21y + -21y

Combine like terms: 21y + -21y = 0
-42 + -21y = 0

Add '42' to each side of the equation.
-42 + 42 + -21y = 0 + 42

Combine like terms: -42 + 42 = 0
0 + -21y = 0 + 42
-21y = 0 + 42

Combine like terms: 0 + 42 = 42
-21y = 42

Divide each side by '-21'.
y = -2

Simplifying
y = -2