r^2-5r+15=0

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Solution for r^2-5r+15=0 equation:


Simplifying
r2 + -5r + 15 = 0

Reorder the terms:
15 + -5r + r2 = 0

Solving
15 + -5r + r2 = 0

Solving for variable 'r'.

Begin completing the square.

Move the constant term to the right:

Add '-15' to each side of the equation.
15 + -5r + -15 + r2 = 0 + -15

Reorder the terms:
15 + -15 + -5r + r2 = 0 + -15

Combine like terms: 15 + -15 = 0
0 + -5r + r2 = 0 + -15
-5r + r2 = 0 + -15

Combine like terms: 0 + -15 = -15
-5r + r2 = -15

The r term is -5r.  Take half its coefficient (-2.5).
Square it (6.25) and add it to both sides.

Add '6.25' to each side of the equation.
-5r + 6.25 + r2 = -15 + 6.25

Reorder the terms:
6.25 + -5r + r2 = -15 + 6.25

Combine like terms: -15 + 6.25 = -8.75
6.25 + -5r + r2 = -8.75

Factor a perfect square on the left side:
(r + -2.5)(r + -2.5) = -8.75

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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