123=3(1+5k)

Solution for 123=3(1+5k) equation:

Simplifying
123 = 3(1 + 5k)
123 = (1 * 3 + 5k * 3)
123 = (3 + 15k)

Solving
123 = 3 + 15k

Solving for variable 'k'.

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

Add '-15k' to each side of the equation.
123 + -15k = 3 + 15k + -15k

Combine like terms: 15k + -15k = 0
123 + -15k = 3 + 0
123 + -15k = 3

Add '-123' to each side of the equation.
123 + -123 + -15k = 3 + -123

Combine like terms: 123 + -123 = 0
0 + -15k = 3 + -123
-15k = 3 + -123

Combine like terms: 3 + -123 = -120
-15k = -120

Divide each side by '-15'.
k = 8

Simplifying
k = 8