81+r^2=(3+r)

Solution for 81+r^2=(3+r) equation:

Simplifying
81 + r2 = (3 + r)

Remove parenthesis around (3 + r)
81 + r2 = 3 + r

Solving
81 + r2 = 3 + r

Solving for variable 'r'.

Reorder the terms:
81 + -3 + -1r + r2 = 3 + r + -3 + -1r

Combine like terms: 81 + -3 = 78
78 + -1r + r2 = 3 + r + -3 + -1r

Reorder the terms:
78 + -1r + r2 = 3 + -3 + r + -1r

Combine like terms: 3 + -3 = 0
78 + -1r + r2 = 0 + r + -1r
78 + -1r + r2 = r + -1r

Combine like terms: r + -1r = 0
78 + -1r + r2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-78' to each side of the equation.
78 + -1r + -78 + r2 = 0 + -78

Reorder the terms:
78 + -78 + -1r + r2 = 0 + -78

Combine like terms: 78 + -78 = 0
0 + -1r + r2 = 0 + -78
-1r + r2 = 0 + -78

Combine like terms: 0 + -78 = -78
-1r + r2 = -78

The r term is -1r.  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.
-1r + 0.25 + r2 = -78 + 0.25

Reorder the terms:
0.25 + -1r + r2 = -78 + 0.25

Combine like terms: -78 + 0.25 = -77.75
0.25 + -1r + r2 = -77.75

Factor a perfect square on the left side:
(r + -0.5)(r + -0.5) = -77.75

Can't calculate square root of the right side.

The solution to this equation could not be determined.