4r*4r+36r+81=r

Solution for 4r*4r+36r+81=r equation:

Simplifying
4r * 4r + 36r + 81 = r

Reorder the terms for easier multiplication:
4 * 4r * r + 36r + 81 = r

Multiply 4 * 4
16r * r + 36r + 81 = r

Multiply r * r
16r2 + 36r + 81 = r

Reorder the terms:
81 + 36r + 16r2 = r

Solving
81 + 36r + 16r2 = r

Solving for variable 'r'.

Reorder the terms:
81 + 36r + -1r + 16r2 = r + -1r

Combine like terms: 36r + -1r = 35r
81 + 35r + 16r2 = r + -1r

Combine like terms: r + -1r = 0
81 + 35r + 16r2 = 0

Begin completing the square.  Divide all terms by
16 the coefficient of the squared term: 

Divide each side by '16'.
5.0625 + 2.1875r + r2 = 0

Move the constant term to the right:

Add '-5.0625' to each side of the equation.
5.0625 + 2.1875r + -5.0625 + r2 = 0 + -5.0625

Reorder the terms:
5.0625 + -5.0625 + 2.1875r + r2 = 0 + -5.0625

Combine like terms: 5.0625 + -5.0625 = 0.0000
0.0000 + 2.1875r + r2 = 0 + -5.0625
2.1875r + r2 = 0 + -5.0625

Combine like terms: 0 + -5.0625 = -5.0625
2.1875r + r2 = -5.0625

The r term is 2.1875r.  Take half its coefficient (1.09375).
Square it (1.196289063) and add it to both sides.

Add '1.196289063' to each side of the equation.
2.1875r + 1.196289063 + r2 = -5.0625 + 1.196289063

Reorder the terms:
1.196289063 + 2.1875r + r2 = -5.0625 + 1.196289063

Combine like terms: -5.0625 + 1.196289063 = -3.866210937
1.196289063 + 2.1875r + r2 = -3.866210937

Factor a perfect square on the left side:
(r + 1.09375)(r + 1.09375) = -3.866210937

Can't calculate square root of the right side.

The solution to this equation could not be determined.