x^3-4x^2+21x=0

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Solution for x^3-4x^2+21x=0 equation:


Simplifying
x3 + -4x2 + 21x = 0

Reorder the terms:
21x + -4x2 + x3 = 0

Solving
21x + -4x2 + x3 = 0

Solving for variable 'x'.

Factor out the Greatest Common Factor (GCF), 'x'.
x(21 + -4x + x2) = 0

Subproblem 1

Set the factor 'x' equal to zero and attempt to solve: Simplifying x = 0 Solving x = 0 Move all terms containing x to the left, all other terms to the right. Simplifying x = 0

Subproblem 2

Set the factor '(21 + -4x + x2)' equal to zero and attempt to solve: Simplifying 21 + -4x + x2 = 0 Solving 21 + -4x + x2 = 0 Begin completing the square. Move the constant term to the right: Add '-21' to each side of the equation. 21 + -4x + -21 + x2 = 0 + -21 Reorder the terms: 21 + -21 + -4x + x2 = 0 + -21 Combine like terms: 21 + -21 = 0 0 + -4x + x2 = 0 + -21 -4x + x2 = 0 + -21 Combine like terms: 0 + -21 = -21 -4x + x2 = -21 The x term is -4x. Take half its coefficient (-2). Square it (4) and add it to both sides. Add '4' to each side of the equation. -4x + 4 + x2 = -21 + 4 Reorder the terms: 4 + -4x + x2 = -21 + 4 Combine like terms: -21 + 4 = -17 4 + -4x + x2 = -17 Factor a perfect square on the left side: (x + -2)(x + -2) = -17 Can't calculate square root of the right side. The solution to this equation could not be determined. This subproblem is being ignored because a solution could not be determined.

Solution

x = {0}

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