123=-3(1-7x)

Solution for 123=-3(1-7x) equation:

Simplifying
123 = -3(1 + -7x)
123 = (1 * -3 + -7x * -3)
123 = (-3 + 21x)

Solving
123 = -3 + 21x

Solving for variable 'x'.

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

Add '-21x' to each side of the equation.
123 + -21x = -3 + 21x + -21x

Combine like terms: 21x + -21x = 0
123 + -21x = -3 + 0
123 + -21x = -3

Add '-123' to each side of the equation.
123 + -123 + -21x = -3 + -123

Combine like terms: 123 + -123 = 0
0 + -21x = -3 + -123
-21x = -3 + -123

Combine like terms: -3 + -123 = -126
-21x = -126

Divide each side by '-21'.
x = 6

Simplifying
x = 6