7r^2-2r-7=-8

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Solution for 7r^2-2r-7=-8 equation:


Simplifying
7r2 + -2r + -7 = -8

Reorder the terms:
-7 + -2r + 7r2 = -8

Solving
-7 + -2r + 7r2 = -8

Solving for variable 'r'.

Reorder the terms:
-7 + 8 + -2r + 7r2 = -8 + 8

Combine like terms: -7 + 8 = 1
1 + -2r + 7r2 = -8 + 8

Combine like terms: -8 + 8 = 0
1 + -2r + 7r2 = 0

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

Divide each side by '7'.
0.1428571429 + -0.2857142857r + r2 = 0

Move the constant term to the right:

Add '-0.1428571429' to each side of the equation.
0.1428571429 + -0.2857142857r + -0.1428571429 + r2 = 0 + -0.1428571429

Reorder the terms:
0.1428571429 + -0.1428571429 + -0.2857142857r + r2 = 0 + -0.1428571429

Combine like terms: 0.1428571429 + -0.1428571429 = 0.0000000000
0.0000000000 + -0.2857142857r + r2 = 0 + -0.1428571429
-0.2857142857r + r2 = 0 + -0.1428571429

Combine like terms: 0 + -0.1428571429 = -0.1428571429
-0.2857142857r + r2 = -0.1428571429

The r term is -0.2857142857r.  Take half its coefficient (-0.1428571429).
Square it (0.02040816328) and add it to both sides.

Add '0.02040816328' to each side of the equation.
-0.2857142857r + 0.02040816328 + r2 = -0.1428571429 + 0.02040816328

Reorder the terms:
0.02040816328 + -0.2857142857r + r2 = -0.1428571429 + 0.02040816328

Combine like terms: -0.1428571429 + 0.02040816328 = -0.12244897962
0.02040816328 + -0.2857142857r + r2 = -0.12244897962

Factor a perfect square on the left side:
(r + -0.1428571429)(r + -0.1428571429) = -0.12244897962

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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