7r^2-14r-7=0

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Solution for 7r^2-14r-7=0 equation:


Simplifying
7r2 + -14r + -7 = 0

Reorder the terms:
-7 + -14r + 7r2 = 0

Solving
-7 + -14r + 7r2 = 0

Solving for variable 'r'.

Factor out the Greatest Common Factor (GCF), '7'.
7(-1 + -2r + r2) = 0

Ignore the factor 7.

Subproblem 1

Set the factor '(-1 + -2r + r2)' equal to zero and attempt to solve: Simplifying -1 + -2r + r2 = 0 Solving -1 + -2r + r2 = 0 Begin completing the square. Move the constant term to the right: Add '1' to each side of the equation. -1 + -2r + 1 + r2 = 0 + 1 Reorder the terms: -1 + 1 + -2r + r2 = 0 + 1 Combine like terms: -1 + 1 = 0 0 + -2r + r2 = 0 + 1 -2r + r2 = 0 + 1 Combine like terms: 0 + 1 = 1 -2r + r2 = 1 The r term is -2r. Take half its coefficient (-1). Square it (1) and add it to both sides. Add '1' to each side of the equation. -2r + 1 + r2 = 1 + 1 Reorder the terms: 1 + -2r + r2 = 1 + 1 Combine like terms: 1 + 1 = 2 1 + -2r + r2 = 2 Factor a perfect square on the left side: (r + -1)(r + -1) = 2 Calculate the square root of the right side: 1.414213562 Break this problem into two subproblems by setting (r + -1) equal to 1.414213562 and -1.414213562.

Subproblem 1

r + -1 = 1.414213562 Simplifying r + -1 = 1.414213562 Reorder the terms: -1 + r = 1.414213562 Solving -1 + r = 1.414213562 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '1' to each side of the equation. -1 + 1 + r = 1.414213562 + 1 Combine like terms: -1 + 1 = 0 0 + r = 1.414213562 + 1 r = 1.414213562 + 1 Combine like terms: 1.414213562 + 1 = 2.414213562 r = 2.414213562 Simplifying r = 2.414213562

Subproblem 2

r + -1 = -1.414213562 Simplifying r + -1 = -1.414213562 Reorder the terms: -1 + r = -1.414213562 Solving -1 + r = -1.414213562 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '1' to each side of the equation. -1 + 1 + r = -1.414213562 + 1 Combine like terms: -1 + 1 = 0 0 + r = -1.414213562 + 1 r = -1.414213562 + 1 Combine like terms: -1.414213562 + 1 = -0.414213562 r = -0.414213562 Simplifying r = -0.414213562

Solution

The solution to the problem is based on the solutions from the subproblems. r = {2.414213562, -0.414213562}

Solution

r = {2.414213562, -0.414213562}

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