a^2-8a-45=0

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Solution for a^2-8a-45=0 equation:


Simplifying
a2 + -8a + -45 = 0

Reorder the terms:
-45 + -8a + a2 = 0

Solving
-45 + -8a + a2 = 0

Solving for variable 'a'.

Begin completing the square.

Move the constant term to the right:

Add '45' to each side of the equation.
-45 + -8a + 45 + a2 = 0 + 45

Reorder the terms:
-45 + 45 + -8a + a2 = 0 + 45

Combine like terms: -45 + 45 = 0
0 + -8a + a2 = 0 + 45
-8a + a2 = 0 + 45

Combine like terms: 0 + 45 = 45
-8a + a2 = 45

The a term is -8a.  Take half its coefficient (-4).
Square it (16) and add it to both sides.

Add '16' to each side of the equation.
-8a + 16 + a2 = 45 + 16

Reorder the terms:
16 + -8a + a2 = 45 + 16

Combine like terms: 45 + 16 = 61
16 + -8a + a2 = 61

Factor a perfect square on the left side:
(a + -4)(a + -4) = 61

Calculate the square root of the right side: 7.810249676

Break this problem into two subproblems by setting 
(a + -4) equal to 7.810249676 and -7.810249676.

Subproblem 1

a + -4 = 7.810249676 Simplifying a + -4 = 7.810249676 Reorder the terms: -4 + a = 7.810249676 Solving -4 + a = 7.810249676 Solving for variable 'a'. Move all terms containing a to the left, all other terms to the right. Add '4' to each side of the equation. -4 + 4 + a = 7.810249676 + 4 Combine like terms: -4 + 4 = 0 0 + a = 7.810249676 + 4 a = 7.810249676 + 4 Combine like terms: 7.810249676 + 4 = 11.810249676 a = 11.810249676 Simplifying a = 11.810249676

Subproblem 2

a + -4 = -7.810249676 Simplifying a + -4 = -7.810249676 Reorder the terms: -4 + a = -7.810249676 Solving -4 + a = -7.810249676 Solving for variable 'a'. Move all terms containing a to the left, all other terms to the right. Add '4' to each side of the equation. -4 + 4 + a = -7.810249676 + 4 Combine like terms: -4 + 4 = 0 0 + a = -7.810249676 + 4 a = -7.810249676 + 4 Combine like terms: -7.810249676 + 4 = -3.810249676 a = -3.810249676 Simplifying a = -3.810249676

Solution

The solution to the problem is based on the solutions from the subproblems. a = {11.810249676, -3.810249676}

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