r^2+r+72=0

Solution for r^2+r+72=0 equation:

Simplifying
r2 + r + 72 = 0

Reorder the terms:
72 + r + r2 = 0

Solving
72 + r + r2 = 0

Solving for variable 'r'.

Begin completing the square.

Move the constant term to the right:

Add '-72' to each side of the equation.
72 + r + -72 + r2 = 0 + -72

Reorder the terms:
72 + -72 + r + r2 = 0 + -72

Combine like terms: 72 + -72 = 0
0 + r + r2 = 0 + -72
r + r2 = 0 + -72

Combine like terms: 0 + -72 = -72
r + r2 = -72

The r term is r.  Take half its coefficient (0.5).
Square it (0.25) and add it to both sides.

Add '0.25' to each side of the equation.
r + 0.25 + r2 = -72 + 0.25

Reorder the terms:
0.25 + r + r2 = -72 + 0.25

Combine like terms: -72 + 0.25 = -71.75
0.25 + r + r2 = -71.75

Factor a perfect square on the left side:
(r + 0.5)(r + 0.5) = -71.75

Can't calculate square root of the right side.

The solution to this equation could not be determined.