0=r^2-4r+45

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Solution for 0=r^2-4r+45 equation:


Simplifying
0 = r2 + -4r + 45

Reorder the terms:
0 = 45 + -4r + r2

Solving
0 = 45 + -4r + r2

Solving for variable 'r'.

Combine like terms: 0 + -45 = -45
-45 + 4r + -1r2 = 45 + -4r + r2 + -45 + 4r + -1r2

Reorder the terms:
-45 + 4r + -1r2 = 45 + -45 + -4r + 4r + r2 + -1r2

Combine like terms: 45 + -45 = 0
-45 + 4r + -1r2 = 0 + -4r + 4r + r2 + -1r2
-45 + 4r + -1r2 = -4r + 4r + r2 + -1r2

Combine like terms: -4r + 4r = 0
-45 + 4r + -1r2 = 0 + r2 + -1r2
-45 + 4r + -1r2 = r2 + -1r2

Combine like terms: r2 + -1r2 = 0
-45 + 4r + -1r2 = 0

Begin completing the square.  Divide all terms by
-1 the coefficient of the squared term: 

Divide each side by '-1'.
45 + -4r + r2 = 0

Move the constant term to the right:

Add '-45' to each side of the equation.
45 + -4r + -45 + r2 = 0 + -45

Reorder the terms:
45 + -45 + -4r + r2 = 0 + -45

Combine like terms: 45 + -45 = 0
0 + -4r + r2 = 0 + -45
-4r + r2 = 0 + -45

Combine like terms: 0 + -45 = -45
-4r + r2 = -45

The r term is -4r.  Take half its coefficient (-2).
Square it (4) and add it to both sides.

Add '4' to each side of the equation.
-4r + 4 + r2 = -45 + 4

Reorder the terms:
4 + -4r + r2 = -45 + 4

Combine like terms: -45 + 4 = -41
4 + -4r + r2 = -41

Factor a perfect square on the left side:
(r + -2)(r + -2) = -41

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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