-x^2+17x+42=0

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Solution for -x^2+17x+42=0 equation:


Simplifying
-1x2 + 17x + 42 = 0

Reorder the terms:
42 + 17x + -1x2 = 0

Solving
42 + 17x + -1x2 = 0

Solving for variable 'x'.

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

Divide each side by '-1'.
-42 + -17x + x2 = 0

Move the constant term to the right:

Add '42' to each side of the equation.
-42 + -17x + 42 + x2 = 0 + 42

Reorder the terms:
-42 + 42 + -17x + x2 = 0 + 42

Combine like terms: -42 + 42 = 0
0 + -17x + x2 = 0 + 42
-17x + x2 = 0 + 42

Combine like terms: 0 + 42 = 42
-17x + x2 = 42

The x term is -17x.  Take half its coefficient (-8.5).
Square it (72.25) and add it to both sides.

Add '72.25' to each side of the equation.
-17x + 72.25 + x2 = 42 + 72.25

Reorder the terms:
72.25 + -17x + x2 = 42 + 72.25

Combine like terms: 42 + 72.25 = 114.25
72.25 + -17x + x2 = 114.25

Factor a perfect square on the left side:
(x + -8.5)(x + -8.5) = 114.25

Calculate the square root of the right side: 10.688779163

Break this problem into two subproblems by setting 
(x + -8.5) equal to 10.688779163 and -10.688779163.

Subproblem 1

x + -8.5 = 10.688779163 Simplifying x + -8.5 = 10.688779163 Reorder the terms: -8.5 + x = 10.688779163 Solving -8.5 + x = 10.688779163 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '8.5' to each side of the equation. -8.5 + 8.5 + x = 10.688779163 + 8.5 Combine like terms: -8.5 + 8.5 = 0.0 0.0 + x = 10.688779163 + 8.5 x = 10.688779163 + 8.5 Combine like terms: 10.688779163 + 8.5 = 19.188779163 x = 19.188779163 Simplifying x = 19.188779163

Subproblem 2

x + -8.5 = -10.688779163 Simplifying x + -8.5 = -10.688779163 Reorder the terms: -8.5 + x = -10.688779163 Solving -8.5 + x = -10.688779163 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '8.5' to each side of the equation. -8.5 + 8.5 + x = -10.688779163 + 8.5 Combine like terms: -8.5 + 8.5 = 0.0 0.0 + x = -10.688779163 + 8.5 x = -10.688779163 + 8.5 Combine like terms: -10.688779163 + 8.5 = -2.188779163 x = -2.188779163 Simplifying x = -2.188779163

Solution

The solution to the problem is based on the solutions from the subproblems. x = {19.188779163, -2.188779163}

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