x^3+3x^2-x+k=0

Solution for x^3+3x^2-x+k=0 equation:

Simplifying
x3 + 3x2 + -1x + k = 0

Reorder the terms:
k + -1x + 3x2 + x3 = 0

Solving
k + -1x + 3x2 + x3 = 0

Solving for variable 'k'.

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

Add 'x' to each side of the equation.
k + -1x + 3x2 + x + x3 = 0 + x

Reorder the terms:
k + -1x + x + 3x2 + x3 = 0 + x

Combine like terms: -1x + x = 0
k + 0 + 3x2 + x3 = 0 + x
k + 3x2 + x3 = 0 + x
Remove the zero:
k + 3x2 + x3 = x

Add '-3x2' to each side of the equation.
k + 3x2 + -3x2 + x3 = x + -3x2

Combine like terms: 3x2 + -3x2 = 0
k + 0 + x3 = x + -3x2
k + x3 = x + -3x2

Add '-1x3' to each side of the equation.
k + x3 + -1x3 = x + -3x2 + -1x3

Combine like terms: x3 + -1x3 = 0
k + 0 = x + -3x2 + -1x3
k = x + -3x2 + -1x3

Simplifying
k = x + -3x2 + -1x3