45=-3(21-z)+3(z-2)

Solution for 45=-3(21-z)+3(z-2) equation:

Simplifying
45 = -3(21 + -1z) + 3(z + -2)
45 = (21 * -3 + -1z * -3) + 3(z + -2)
45 = (-63 + 3z) + 3(z + -2)

Reorder the terms:
45 = -63 + 3z + 3(-2 + z)
45 = -63 + 3z + (-2 * 3 + z * 3)
45 = -63 + 3z + (-6 + 3z)

Reorder the terms:
45 = -63 + -6 + 3z + 3z

Combine like terms: -63 + -6 = -69
45 = -69 + 3z + 3z

Combine like terms: 3z + 3z = 6z
45 = -69 + 6z

Solving
45 = -69 + 6z

Solving for variable 'z'.

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

Add '-6z' to each side of the equation.
45 + -6z = -69 + 6z + -6z

Combine like terms: 6z + -6z = 0
45 + -6z = -69 + 0
45 + -6z = -69

Add '-45' to each side of the equation.
45 + -45 + -6z = -69 + -45

Combine like terms: 45 + -45 = 0
0 + -6z = -69 + -45
-6z = -69 + -45

Combine like terms: -69 + -45 = -114
-6z = -114

Divide each side by '-6'.
z = 19

Simplifying
z = 19