x^2-21x-49=0

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Solution for x^2-21x-49=0 equation:


Simplifying
x2 + -21x + -49 = 0

Reorder the terms:
-49 + -21x + x2 = 0

Solving
-49 + -21x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '49' to each side of the equation.
-49 + -21x + 49 + x2 = 0 + 49

Reorder the terms:
-49 + 49 + -21x + x2 = 0 + 49

Combine like terms: -49 + 49 = 0
0 + -21x + x2 = 0 + 49
-21x + x2 = 0 + 49

Combine like terms: 0 + 49 = 49
-21x + x2 = 49

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 = 49 + 110.25

Reorder the terms:
110.25 + -21x + x2 = 49 + 110.25

Combine like terms: 49 + 110.25 = 159.25
110.25 + -21x + x2 = 159.25

Factor a perfect square on the left side:
(x + -10.5)(x + -10.5) = 159.25

Calculate the square root of the right side: 12.619429464

Break this problem into two subproblems by setting 
(x + -10.5) equal to 12.619429464 and -12.619429464.

Subproblem 1

x + -10.5 = 12.619429464 Simplifying x + -10.5 = 12.619429464 Reorder the terms: -10.5 + x = 12.619429464 Solving -10.5 + x = 12.619429464 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 = 12.619429464 + 10.5 Combine like terms: -10.5 + 10.5 = 0.0 0.0 + x = 12.619429464 + 10.5 x = 12.619429464 + 10.5 Combine like terms: 12.619429464 + 10.5 = 23.119429464 x = 23.119429464 Simplifying x = 23.119429464

Subproblem 2

x + -10.5 = -12.619429464 Simplifying x + -10.5 = -12.619429464 Reorder the terms: -10.5 + x = -12.619429464 Solving -10.5 + x = -12.619429464 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 = -12.619429464 + 10.5 Combine like terms: -10.5 + 10.5 = 0.0 0.0 + x = -12.619429464 + 10.5 x = -12.619429464 + 10.5 Combine like terms: -12.619429464 + 10.5 = -2.119429464 x = -2.119429464 Simplifying x = -2.119429464

Solution

The solution to the problem is based on the solutions from the subproblems. x = {23.119429464, -2.119429464}

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