8k^2+22k-21=0

Solution for 8k^2+22k-21=0 equation:

Simplifying
8k2 + 22k + -21 = 0

Reorder the terms:
-21 + 22k + 8k2 = 0

Solving
-21 + 22k + 8k2 = 0

Solving for variable 'k'.

Factor a trinomial.
(-7 + -2k)(3 + -4k) = 0

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

Simplifying
-7 + -2k = 0

Solving
-7 + -2k = 0

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

Add '7' to each side of the equation.
-7 + 7 + -2k = 0 + 7

Combine like terms: -7 + 7 = 0
0 + -2k = 0 + 7
-2k = 0 + 7

Combine like terms: 0 + 7 = 7
-2k = 7

Divide each side by '-2'.
k = -3.5

Simplifying
k = -3.5
Subproblem 2
Set the factor '(3 + -4k)' equal to zero and attempt to solve:

Simplifying
3 + -4k = 0

Solving
3 + -4k = 0

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

Add '-3' to each side of the equation.
3 + -3 + -4k = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -4k = 0 + -3
-4k = 0 + -3

Combine like terms: 0 + -3 = -3
-4k = -3

Divide each side by '-4'.
k = 0.75

Simplifying
k = 0.75
Solution
k = {-3.5, 0.75}