x^2-21x-98=0

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Solution for x^2-21x-98=0 equation: 


Simplifying
x2 + -21x + -98 = 0

Reorder the terms:
-98 + -21x + x2 = 0

Solving
-98 + -21x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '98' to each side of the equation.
-98 + -21x + 98 + x2 = 0 + 98

Reorder the terms:
-98 + 98 + -21x + x2 = 0 + 98

Combine like terms: -98 + 98 = 0
0 + -21x + x2 = 0 + 98
-21x + x2 = 0 + 98

Combine like terms: 0 + 98 = 98
-21x + x2 = 98

The x term is -21x.  Take half its coefficient (-10.5).
Square it (110.25) and add it to both sides.

Add '110.25' to each side of the equation.
-21x + 110.25 + x2 = 98 + 110.25

Reorder the terms:
110.25 + -21x + x2 = 98 + 110.25

Combine like terms: 98 + 110.25 = 208.25
110.25 + -21x + x2 = 208.25

Factor a perfect square on the left side:
(x + -10.5)(x + -10.5) = 208.25

Calculate the square root of the right side: 14.43086969

Break this problem into two subproblems by setting 
(x + -10.5) equal to 14.43086969 and -14.43086969.


Subproblem 1
x + -10.5 = 14.43086969

Simplifying
x + -10.5 = 14.43086969

Reorder the terms:
-10.5 + x = 14.43086969

Solving
-10.5 + x = 14.43086969

Solving for variable 'x'.

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

Add '10.5' to each side of the equation.
-10.5 + 10.5 + x = 14.43086969 + 10.5

Combine like terms: -10.5 + 10.5 = 0.0
0.0 + x = 14.43086969 + 10.5
x = 14.43086969 + 10.5

Combine like terms: 14.43086969 + 10.5 = 24.93086969
x = 24.93086969

Simplifying
x = 24.93086969


Subproblem 2
x + -10.5 = -14.43086969

Simplifying
x + -10.5 = -14.43086969

Reorder the terms:
-10.5 + x = -14.43086969

Solving
-10.5 + x = -14.43086969

Solving for variable 'x'.

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

Add '10.5' to each side of the equation.
-10.5 + 10.5 + x = -14.43086969 + 10.5

Combine like terms: -10.5 + 10.5 = 0.0
0.0 + x = -14.43086969 + 10.5
x = -14.43086969 + 10.5

Combine like terms: -14.43086969 + 10.5 = -3.93086969
x = -3.93086969

Simplifying
x = -3.93086969


Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {24.93086969, -3.93086969}

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