4+z+2=21+-2z

Solution for 4+z+2=21+-2z equation:

Simplifying
4 + z + 2 = 21 + -2z

Reorder the terms:
4 + 2 + z = 21 + -2z

Combine like terms: 4 + 2 = 6
6 + z = 21 + -2z

Solving
6 + z = 21 + -2z

Solving for variable 'z'.

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

Add '2z' to each side of the equation.
6 + z + 2z = 21 + -2z + 2z

Combine like terms: z + 2z = 3z
6 + 3z = 21 + -2z + 2z

Combine like terms: -2z + 2z = 0
6 + 3z = 21 + 0
6 + 3z = 21

Add '-6' to each side of the equation.
6 + -6 + 3z = 21 + -6

Combine like terms: 6 + -6 = 0
0 + 3z = 21 + -6
3z = 21 + -6

Combine like terms: 21 + -6 = 15
3z = 15

Divide each side by '3'.
z = 5

Simplifying
z = 5