r^2+2r-25=0

Solution for r^2+2r-25=0 equation:

Simplifying
r2 + 2r + -25 = 0

Reorder the terms:
-25 + 2r + r2 = 0

Solving
-25 + 2r + r2 = 0

Solving for variable 'r'.

Begin completing the square.

Move the constant term to the right:

Add '25' to each side of the equation.
-25 + 2r + 25 + r2 = 0 + 25

Reorder the terms:
-25 + 25 + 2r + r2 = 0 + 25

Combine like terms: -25 + 25 = 0
0 + 2r + r2 = 0 + 25
2r + r2 = 0 + 25

Combine like terms: 0 + 25 = 25
2r + r2 = 25

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 = 25 + 1

Reorder the terms:
1 + 2r + r2 = 25 + 1

Combine like terms: 25 + 1 = 26
1 + 2r + r2 = 26

Factor a perfect square on the left side:
(r + 1)(r + 1) = 26

Calculate the square root of the right side: 5.099019514

Break this problem into two subproblems by setting 
(r + 1) equal to 5.099019514 and -5.099019514.

Subproblem 1
r + 1 = 5.099019514

Simplifying
r + 1 = 5.099019514

Reorder the terms:
1 + r = 5.099019514

Solving
1 + r = 5.099019514

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 = 5.099019514 + -1

Combine like terms: 1 + -1 = 0
0 + r = 5.099019514 + -1
r = 5.099019514 + -1

Combine like terms: 5.099019514 + -1 = 4.099019514
r = 4.099019514

Simplifying
r = 4.099019514

Subproblem 2
r + 1 = -5.099019514

Simplifying
r + 1 = -5.099019514

Reorder the terms:
1 + r = -5.099019514

Solving
1 + r = -5.099019514

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 = -5.099019514 + -1

Combine like terms: 1 + -1 = 0
0 + r = -5.099019514 + -1
r = -5.099019514 + -1

Combine like terms: -5.099019514 + -1 = -6.099019514
r = -6.099019514

Simplifying
r = -6.099019514

Solution
The solution to the problem is based on the solutions
from the subproblems.
r = {4.099019514, -6.099019514}