4x^2-16x-21=12

Solution for 4x^2-16x-21=12 equation:

Simplifying
4x2 + -16x + -21 = 12

Reorder the terms:
-21 + -16x + 4x2 = 12

Solving
-21 + -16x + 4x2 = 12

Solving for variable 'x'.

Reorder the terms:
-21 + -12 + -16x + 4x2 = 12 + -12

Combine like terms: -21 + -12 = -33
-33 + -16x + 4x2 = 12 + -12

Combine like terms: 12 + -12 = 0
-33 + -16x + 4x2 = 0

Factor a trinomial.
(-3 + -2x)(11 + -2x) = 0

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

Simplifying
-3 + -2x = 0

Solving
-3 + -2x = 0

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

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

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

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

Divide each side by '-2'.
x = -1.5

Simplifying
x = -1.5
Subproblem 2
Set the factor '(11 + -2x)' equal to zero and attempt to solve:

Simplifying
11 + -2x = 0

Solving
11 + -2x = 0

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

Add '-11' to each side of the equation.
11 + -11 + -2x = 0 + -11

Combine like terms: 11 + -11 = 0
0 + -2x = 0 + -11
-2x = 0 + -11

Combine like terms: 0 + -11 = -11
-2x = -11

Divide each side by '-2'.
x = 5.5

Simplifying
x = 5.5
Solution
x = {-1.5, 5.5}