x^2+20x-78=0

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Solution for x^2+20x-78=0 equation:


Simplifying
x2 + 20x + -78 = 0

Reorder the terms:
-78 + 20x + x2 = 0

Solving
-78 + 20x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '78' to each side of the equation.
-78 + 20x + 78 + x2 = 0 + 78

Reorder the terms:
-78 + 78 + 20x + x2 = 0 + 78

Combine like terms: -78 + 78 = 0
0 + 20x + x2 = 0 + 78
20x + x2 = 0 + 78

Combine like terms: 0 + 78 = 78
20x + x2 = 78

The x term is 20x.  Take half its coefficient (10).
Square it (100) and add it to both sides.

Add '100' to each side of the equation.
20x + 100 + x2 = 78 + 100

Reorder the terms:
100 + 20x + x2 = 78 + 100

Combine like terms: 78 + 100 = 178
100 + 20x + x2 = 178

Factor a perfect square on the left side:
(x + 10)(x + 10) = 178

Calculate the square root of the right side: 13.341664064

Break this problem into two subproblems by setting 
(x + 10) equal to 13.341664064 and -13.341664064.

Subproblem 1

x + 10 = 13.341664064 Simplifying x + 10 = 13.341664064 Reorder the terms: 10 + x = 13.341664064 Solving 10 + x = 13.341664064 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-10' to each side of the equation. 10 + -10 + x = 13.341664064 + -10 Combine like terms: 10 + -10 = 0 0 + x = 13.341664064 + -10 x = 13.341664064 + -10 Combine like terms: 13.341664064 + -10 = 3.341664064 x = 3.341664064 Simplifying x = 3.341664064

Subproblem 2

x + 10 = -13.341664064 Simplifying x + 10 = -13.341664064 Reorder the terms: 10 + x = -13.341664064 Solving 10 + x = -13.341664064 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-10' to each side of the equation. 10 + -10 + x = -13.341664064 + -10 Combine like terms: 10 + -10 = 0 0 + x = -13.341664064 + -10 x = -13.341664064 + -10 Combine like terms: -13.341664064 + -10 = -23.341664064 x = -23.341664064 Simplifying x = -23.341664064

Solution

The solution to the problem is based on the solutions from the subproblems. x = {3.341664064, -23.341664064}

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