3x^2-7x-12=0

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Solution for 3x^2-7x-12=0 equation:


Simplifying
3x2 + -7x + -12 = 0

Reorder the terms:
-12 + -7x + 3x2 = 0

Solving
-12 + -7x + 3x2 = 0

Solving for variable 'x'.

Begin completing the square.  Divide all terms by
3 the coefficient of the squared term: 

Divide each side by '3'.
-4 + -2.333333333x + x2 = 0

Move the constant term to the right:

Add '4' to each side of the equation.
-4 + -2.333333333x + 4 + x2 = 0 + 4

Reorder the terms:
-4 + 4 + -2.333333333x + x2 = 0 + 4

Combine like terms: -4 + 4 = 0
0 + -2.333333333x + x2 = 0 + 4
-2.333333333x + x2 = 0 + 4

Combine like terms: 0 + 4 = 4
-2.333333333x + x2 = 4

The x term is -2.333333333x.  Take half its coefficient (-1.166666667).
Square it (1.361111112) and add it to both sides.

Add '1.361111112' to each side of the equation.
-2.333333333x + 1.361111112 + x2 = 4 + 1.361111112

Reorder the terms:
1.361111112 + -2.333333333x + x2 = 4 + 1.361111112

Combine like terms: 4 + 1.361111112 = 5.361111112
1.361111112 + -2.333333333x + x2 = 5.361111112

Factor a perfect square on the left side:
(x + -1.166666667)(x + -1.166666667) = 5.361111112

Calculate the square root of the right side: 2.315407332

Break this problem into two subproblems by setting 
(x + -1.166666667) equal to 2.315407332 and -2.315407332.

Subproblem 1

x + -1.166666667 = 2.315407332 Simplifying x + -1.166666667 = 2.315407332 Reorder the terms: -1.166666667 + x = 2.315407332 Solving -1.166666667 + x = 2.315407332 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.166666667' to each side of the equation. -1.166666667 + 1.166666667 + x = 2.315407332 + 1.166666667 Combine like terms: -1.166666667 + 1.166666667 = 0.000000000 0.000000000 + x = 2.315407332 + 1.166666667 x = 2.315407332 + 1.166666667 Combine like terms: 2.315407332 + 1.166666667 = 3.482073999 x = 3.482073999 Simplifying x = 3.482073999

Subproblem 2

x + -1.166666667 = -2.315407332 Simplifying x + -1.166666667 = -2.315407332 Reorder the terms: -1.166666667 + x = -2.315407332 Solving -1.166666667 + x = -2.315407332 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.166666667' to each side of the equation. -1.166666667 + 1.166666667 + x = -2.315407332 + 1.166666667 Combine like terms: -1.166666667 + 1.166666667 = 0.000000000 0.000000000 + x = -2.315407332 + 1.166666667 x = -2.315407332 + 1.166666667 Combine like terms: -2.315407332 + 1.166666667 = -1.148740665 x = -1.148740665 Simplifying x = -1.148740665

Solution

The solution to the problem is based on the solutions from the subproblems. x = {3.482073999, -1.148740665}

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