-21x^2-18x=0

Solution for -21x^2-18x=0 equation:

Simplifying
-21x2 + -18x = 0

Reorder the terms:
-18x + -21x2 = 0

Solving
-18x + -21x2 = 0

Solving for variable 'x'.

Factor out the Greatest Common Factor (GCF), '-3x'.
-3x(6 + 7x) = 0

Ignore the factor -3.
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 '(6 + 7x)' equal to zero and attempt to solve:

Simplifying
6 + 7x = 0

Solving
6 + 7x = 0

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

Add '-6' to each side of the equation.
6 + -6 + 7x = 0 + -6

Combine like terms: 6 + -6 = 0
0 + 7x = 0 + -6
7x = 0 + -6

Combine like terms: 0 + -6 = -6
7x = -6

Divide each side by '7'.
x = -0.8571428571

Simplifying
x = -0.8571428571
Solution
x = {0, -0.8571428571}