=7x^3-28x

Solution for =7x^3-28x equation:

Simplifying
0 = 7x3 + -28x

Reorder the terms:
0 = -28x + 7x3

Solving
0 = -28x + 7x3

Solving for variable 'x'.
Remove the zero:
28x + -7x3 = -28x + 7x3 + 28x + -7x3

Reorder the terms:
28x + -7x3 = -28x + 28x + 7x3 + -7x3

Combine like terms: -28x + 28x = 0
28x + -7x3 = 0 + 7x3 + -7x3
28x + -7x3 = 7x3 + -7x3

Combine like terms: 7x3 + -7x3 = 0
28x + -7x3 = 0

Factor out the Greatest Common Factor (GCF), '7x'.
7x(4 + -1x2) = 0

Factor a difference between two squares.
7x((2 + x)(2 + -1x)) = 0

Ignore the factor 7.
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 '(2 + x)' equal to zero and attempt to solve:

Simplifying
2 + x = 0

Solving
2 + x = 0

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

Add '-2' to each side of the equation.
2 + -2 + x = 0 + -2

Combine like terms: 2 + -2 = 0
0 + x = 0 + -2
x = 0 + -2

Combine like terms: 0 + -2 = -2
x = -2

Simplifying
x = -2
Subproblem 3
Set the factor '(2 + -1x)' equal to zero and attempt to solve:

Simplifying
2 + -1x = 0

Solving
2 + -1x = 0

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

Add '-2' to each side of the equation.
2 + -2 + -1x = 0 + -2

Combine like terms: 2 + -2 = 0
0 + -1x = 0 + -2
-1x = 0 + -2

Combine like terms: 0 + -2 = -2
-1x = -2

Divide each side by '-1'.
x = 2

Simplifying
x = 2
Solution
x = {0, -2, 2}