r^2-2r-1=-4

Solution for r^2-2r-1=-4 equation:

Simplifying
r2 + -2r + -1 = -4

Reorder the terms:
-1 + -2r + r2 = -4

Solving
-1 + -2r + r2 = -4

Solving for variable 'r'.

Reorder the terms:
-1 + 4 + -2r + r2 = -4 + 4

Combine like terms: -1 + 4 = 3
3 + -2r + r2 = -4 + 4

Combine like terms: -4 + 4 = 0
3 + -2r + r2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-3' to each side of the equation.
3 + -2r + -3 + r2 = 0 + -3

Reorder the terms:
3 + -3 + -2r + r2 = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -2r + r2 = 0 + -3
-2r + r2 = 0 + -3

Combine like terms: 0 + -3 = -3
-2r + r2 = -3

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 = -3 + 1

Reorder the terms:
1 + -2r + r2 = -3 + 1

Combine like terms: -3 + 1 = -2
1 + -2r + r2 = -2

Factor a perfect square on the left side:
(r + -1)(r + -1) = -2

Can't calculate square root of the right side.

The solution to this equation could not be determined.