84=x^2+4x(2)

Solution for 84=x^2+4x(2) equation:

Simplifying
84 = x2 + 4x(2)

Reorder the terms for easier multiplication:
84 = x2 + 4 * 2x

Multiply 4 * 2
84 = x2 + 8x

Reorder the terms:
84 = 8x + x2

Solving
84 = 8x + x2

Solving for variable 'x'.

Reorder the terms:
84 + -8x + -1x2 = 8x + -8x + x2 + -1x2

Combine like terms: 8x + -8x = 0
84 + -8x + -1x2 = 0 + x2 + -1x2
84 + -8x + -1x2 = x2 + -1x2

Combine like terms: x2 + -1x2 = 0
84 + -8x + -1x2 = 0

Factor a trinomial.
(6 + -1x)(14 + x) = 0

Subproblem 1
Set the factor '(6 + -1x)' equal to zero and attempt to solve:

Simplifying
6 + -1x = 0

Solving
6 + -1x = 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 + -1x = 0 + -6

Combine like terms: 6 + -6 = 0
0 + -1x = 0 + -6
-1x = 0 + -6

Combine like terms: 0 + -6 = -6
-1x = -6

Divide each side by '-1'.
x = 6

Simplifying
x = 6
Subproblem 2
Set the factor '(14 + x)' equal to zero and attempt to solve:

Simplifying
14 + x = 0

Solving
14 + x = 0

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

Add '-14' to each side of the equation.
14 + -14 + x = 0 + -14

Combine like terms: 14 + -14 = 0
0 + x = 0 + -14
x = 0 + -14

Combine like terms: 0 + -14 = -14
x = -14

Simplifying
x = -14
Solution
x = {6, -14}