r^2+2r+15=0

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Solution for r^2+2r+15=0 equation:


Simplifying
r2 + 2r + 15 = 0

Reorder the terms:
15 + 2r + r2 = 0

Solving
15 + 2r + r2 = 0

Solving for variable 'r'.

Begin completing the square.

Move the constant term to the right:

Add '-15' to each side of the equation.
15 + 2r + -15 + r2 = 0 + -15

Reorder the terms:
15 + -15 + 2r + r2 = 0 + -15

Combine like terms: 15 + -15 = 0
0 + 2r + r2 = 0 + -15
2r + r2 = 0 + -15

Combine like terms: 0 + -15 = -15
2r + r2 = -15

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 = -15 + 1

Reorder the terms:
1 + 2r + r2 = -15 + 1

Combine like terms: -15 + 1 = -14
1 + 2r + r2 = -14

Factor a perfect square on the left side:
(r + 1)(r + 1) = -14

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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