21k^2+11k-2=0

Solution for 21k^2+11k-2=0 equation:

Simplifying
21k2 + 11k + -2 = 0

Reorder the terms:
-2 + 11k + 21k2 = 0

Solving
-2 + 11k + 21k2 = 0

Solving for variable 'k'.

Factor a trinomial.
(-2 + -3k)(1 + -7k) = 0

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

Simplifying
-2 + -3k = 0

Solving
-2 + -3k = 0

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

Add '2' to each side of the equation.
-2 + 2 + -3k = 0 + 2

Combine like terms: -2 + 2 = 0
0 + -3k = 0 + 2
-3k = 0 + 2

Combine like terms: 0 + 2 = 2
-3k = 2

Divide each side by '-3'.
k = -0.6666666667

Simplifying
k = -0.6666666667
Subproblem 2
Set the factor '(1 + -7k)' equal to zero and attempt to solve:

Simplifying
1 + -7k = 0

Solving
1 + -7k = 0

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

Add '-1' to each side of the equation.
1 + -1 + -7k = 0 + -1

Combine like terms: 1 + -1 = 0
0 + -7k = 0 + -1
-7k = 0 + -1

Combine like terms: 0 + -1 = -1
-7k = -1

Divide each side by '-7'.
k = 0.1428571429

Simplifying
k = 0.1428571429
Solution
k = {-0.6666666667, 0.1428571429}