3x^2-42x-72=0

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Solution for 3x^2-42x-72=0 equation: 


Simplifying
3x2 + -42x + -72 = 0

Reorder the terms:
-72 + -42x + 3x2 = 0

Solving
-72 + -42x + 3x2 = 0

Solving for variable 'x'.

Factor out the Greatest Common Factor (GCF), '3'.
3(-24 + -14x + x2) = 0

Ignore the factor 3.

Subproblem 1
Set the factor '(-24 + -14x + x2)' equal to zero and attempt to solve:

Simplifying
-24 + -14x + x2 = 0

Solving
-24 + -14x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '24' to each side of the equation.
-24 + -14x + 24 + x2 = 0 + 24

Reorder the terms:
-24 + 24 + -14x + x2 = 0 + 24

Combine like terms: -24 + 24 = 0
0 + -14x + x2 = 0 + 24
-14x + x2 = 0 + 24

Combine like terms: 0 + 24 = 24
-14x + x2 = 24

The x term is -14x.  Take half its coefficient (-7).
Square it (49) and add it to both sides.

Add '49' to each side of the equation.
-14x + 49 + x2 = 24 + 49

Reorder the terms:
49 + -14x + x2 = 24 + 49

Combine like terms: 24 + 49 = 73
49 + -14x + x2 = 73

Factor a perfect square on the left side:
(x + -7)(x + -7) = 73

Calculate the square root of the right side: 8.544003745

Break this problem into two subproblems by setting 
(x + -7) equal to 8.544003745 and -8.544003745.


Subproblem 1
x + -7 = 8.544003745

Simplifying
x + -7 = 8.544003745

Reorder the terms:
-7 + x = 8.544003745

Solving
-7 + x = 8.544003745

Solving for variable 'x'.

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

Add '7' to each side of the equation.
-7 + 7 + x = 8.544003745 + 7

Combine like terms: -7 + 7 = 0
0 + x = 8.544003745 + 7
x = 8.544003745 + 7

Combine like terms: 8.544003745 + 7 = 15.544003745
x = 15.544003745

Simplifying
x = 15.544003745


Subproblem 2
x + -7 = -8.544003745

Simplifying
x + -7 = -8.544003745

Reorder the terms:
-7 + x = -8.544003745

Solving
-7 + x = -8.544003745

Solving for variable 'x'.

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

Add '7' to each side of the equation.
-7 + 7 + x = -8.544003745 + 7

Combine like terms: -7 + 7 = 0
0 + x = -8.544003745 + 7
x = -8.544003745 + 7

Combine like terms: -8.544003745 + 7 = -1.544003745
x = -1.544003745

Simplifying
x = -1.544003745


Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {15.544003745, -1.544003745}
Solution
x = {15.544003745, -1.544003745}

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