r^2-14r+39=-90

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Solution for r^2-14r+39=-90 equation:


Simplifying
r2 + -14r + 39 = -90

Reorder the terms:
39 + -14r + r2 = -90

Solving
39 + -14r + r2 = -90

Solving for variable 'r'.

Reorder the terms:
39 + 90 + -14r + r2 = -90 + 90

Combine like terms: 39 + 90 = 129
129 + -14r + r2 = -90 + 90

Combine like terms: -90 + 90 = 0
129 + -14r + r2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-129' to each side of the equation.
129 + -14r + -129 + r2 = 0 + -129

Reorder the terms:
129 + -129 + -14r + r2 = 0 + -129

Combine like terms: 129 + -129 = 0
0 + -14r + r2 = 0 + -129
-14r + r2 = 0 + -129

Combine like terms: 0 + -129 = -129
-14r + r2 = -129

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

Add '49' to each side of the equation.
-14r + 49 + r2 = -129 + 49

Reorder the terms:
49 + -14r + r2 = -129 + 49

Combine like terms: -129 + 49 = -80
49 + -14r + r2 = -80

Factor a perfect square on the left side:
(r + -7)(r + -7) = -80

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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