2(h*h)+h=21

Solution for 2(h*h)+h=21 equation:

Simplifying
2(h * h) + h = 21

Multiply h * h
2(h2) + h = 21

Reorder the terms:
h + 2h2 = 21

Solving
h + 2h2 = 21

Solving for variable 'h'.

Reorder the terms:
-21 + h + 2h2 = 21 + -21

Combine like terms: 21 + -21 = 0
-21 + h + 2h2 = 0

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

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

Simplifying
-7 + -2h = 0

Solving
-7 + -2h = 0

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

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

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

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

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

Simplifying
h = -3.5
Subproblem 2
Set the factor '(3 + -1h)' equal to zero and attempt to solve:

Simplifying
3 + -1h = 0

Solving
3 + -1h = 0

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

Add '-3' to each side of the equation.
3 + -3 + -1h = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -1h = 0 + -3
-1h = 0 + -3

Combine like terms: 0 + -3 = -3
-1h = -3

Divide each side by '-1'.
h = 3

Simplifying
h = 3
Solution
h = {-3.5, 3}