9x^2+21x=6

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Solution for 9x^2+21x=6 equation:


Simplifying
9x2 + 21x = 6

Reorder the terms:
21x + 9x2 = 6

Solving
21x + 9x2 = 6

Solving for variable 'x'.

Reorder the terms:
-6 + 21x + 9x2 = 6 + -6

Combine like terms: 6 + -6 = 0
-6 + 21x + 9x2 = 0

Factor out the Greatest Common Factor (GCF), '3'.
3(-2 + 7x + 3x2) = 0

Ignore the factor 3.

Subproblem 1

Set the factor '(-2 + 7x + 3x2)' equal to zero and attempt to solve: Simplifying -2 + 7x + 3x2 = 0 Solving -2 + 7x + 3x2 = 0 Begin completing the square. Divide all terms by 3 the coefficient of the squared term: Divide each side by '3'. -0.6666666667 + 2.333333333x + x2 = 0 Move the constant term to the right: Add '0.6666666667' to each side of the equation. -0.6666666667 + 2.333333333x + 0.6666666667 + x2 = 0 + 0.6666666667 Reorder the terms: -0.6666666667 + 0.6666666667 + 2.333333333x + x2 = 0 + 0.6666666667 Combine like terms: -0.6666666667 + 0.6666666667 = 0.0000000000 0.0000000000 + 2.333333333x + x2 = 0 + 0.6666666667 2.333333333x + x2 = 0 + 0.6666666667 Combine like terms: 0 + 0.6666666667 = 0.6666666667 2.333333333x + x2 = 0.6666666667 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 = 0.6666666667 + 1.361111112 Reorder the terms: 1.361111112 + 2.333333333x + x2 = 0.6666666667 + 1.361111112 Combine like terms: 0.6666666667 + 1.361111112 = 2.0277777787 1.361111112 + 2.333333333x + x2 = 2.0277777787 Factor a perfect square on the left side: (x + 1.166666667)(x + 1.166666667) = 2.0277777787 Calculate the square root of the right side: 1.424000625 Break this problem into two subproblems by setting (x + 1.166666667) equal to 1.424000625 and -1.424000625.

Subproblem 1

x + 1.166666667 = 1.424000625 Simplifying x + 1.166666667 = 1.424000625 Reorder the terms: 1.166666667 + x = 1.424000625 Solving 1.166666667 + x = 1.424000625 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 = 1.424000625 + -1.166666667 Combine like terms: 1.166666667 + -1.166666667 = 0.000000000 0.000000000 + x = 1.424000625 + -1.166666667 x = 1.424000625 + -1.166666667 Combine like terms: 1.424000625 + -1.166666667 = 0.257333958 x = 0.257333958 Simplifying x = 0.257333958

Subproblem 2

x + 1.166666667 = -1.424000625 Simplifying x + 1.166666667 = -1.424000625 Reorder the terms: 1.166666667 + x = -1.424000625 Solving 1.166666667 + x = -1.424000625 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 = -1.424000625 + -1.166666667 Combine like terms: 1.166666667 + -1.166666667 = 0.000000000 0.000000000 + x = -1.424000625 + -1.166666667 x = -1.424000625 + -1.166666667 Combine like terms: -1.424000625 + -1.166666667 = -2.590667292 x = -2.590667292 Simplifying x = -2.590667292

Solution

The solution to the problem is based on the solutions from the subproblems. x = {0.257333958, -2.590667292}

Solution

x = {0.257333958, -2.590667292}

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