5r^2-r+9=0

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Solution for 5r^2-r+9=0 equation:


Simplifying
5r2 + -1r + 9 = 0

Reorder the terms:
9 + -1r + 5r2 = 0

Solving
9 + -1r + 5r2 = 0

Solving for variable 'r'.

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

Divide each side by '5'.
1.8 + -0.2r + r2 = 0

Move the constant term to the right:

Add '-1.8' to each side of the equation.
1.8 + -0.2r + -1.8 + r2 = 0 + -1.8

Reorder the terms:
1.8 + -1.8 + -0.2r + r2 = 0 + -1.8

Combine like terms: 1.8 + -1.8 = 0.0
0.0 + -0.2r + r2 = 0 + -1.8
-0.2r + r2 = 0 + -1.8

Combine like terms: 0 + -1.8 = -1.8
-0.2r + r2 = -1.8

The r term is -0.2r.  Take half its coefficient (-0.1).
Square it (0.01) and add it to both sides.

Add '0.01' to each side of the equation.
-0.2r + 0.01 + r2 = -1.8 + 0.01

Reorder the terms:
0.01 + -0.2r + r2 = -1.8 + 0.01

Combine like terms: -1.8 + 0.01 = -1.79
0.01 + -0.2r + r2 = -1.79

Factor a perfect square on the left side:
(r + -0.1)(r + -0.1) = -1.79

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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