a^2-18a+9=0

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Solution for a^2-18a+9=0 equation:


Simplifying
a2 + -18a + 9 = 0

Reorder the terms:
9 + -18a + a2 = 0

Solving
9 + -18a + a2 = 0

Solving for variable 'a'.

Begin completing the square.

Move the constant term to the right:

Add '-9' to each side of the equation.
9 + -18a + -9 + a2 = 0 + -9

Reorder the terms:
9 + -9 + -18a + a2 = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -18a + a2 = 0 + -9
-18a + a2 = 0 + -9

Combine like terms: 0 + -9 = -9
-18a + a2 = -9

The a term is -18a.  Take half its coefficient (-9).
Square it (81) and add it to both sides.

Add '81' to each side of the equation.
-18a + 81 + a2 = -9 + 81

Reorder the terms:
81 + -18a + a2 = -9 + 81

Combine like terms: -9 + 81 = 72
81 + -18a + a2 = 72

Factor a perfect square on the left side:
(a + -9)(a + -9) = 72

Calculate the square root of the right side: 8.485281374

Break this problem into two subproblems by setting 
(a + -9) equal to 8.485281374 and -8.485281374.

Subproblem 1

a + -9 = 8.485281374 Simplifying a + -9 = 8.485281374 Reorder the terms: -9 + a = 8.485281374 Solving -9 + a = 8.485281374 Solving for variable 'a'. Move all terms containing a to the left, all other terms to the right. Add '9' to each side of the equation. -9 + 9 + a = 8.485281374 + 9 Combine like terms: -9 + 9 = 0 0 + a = 8.485281374 + 9 a = 8.485281374 + 9 Combine like terms: 8.485281374 + 9 = 17.485281374 a = 17.485281374 Simplifying a = 17.485281374

Subproblem 2

a + -9 = -8.485281374 Simplifying a + -9 = -8.485281374 Reorder the terms: -9 + a = -8.485281374 Solving -9 + a = -8.485281374 Solving for variable 'a'. Move all terms containing a to the left, all other terms to the right. Add '9' to each side of the equation. -9 + 9 + a = -8.485281374 + 9 Combine like terms: -9 + 9 = 0 0 + a = -8.485281374 + 9 a = -8.485281374 + 9 Combine like terms: -8.485281374 + 9 = 0.514718626 a = 0.514718626 Simplifying a = 0.514718626

Solution

The solution to the problem is based on the solutions from the subproblems. a = {17.485281374, 0.514718626}

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