-x^2+8x+31=0

Simple and best practice solution for -x^2+8x+31=0 equation. Check how easy it is, and learn it for the future. Our solution is simple, and easy to understand, so don`t hesitate to use it as a solution of your homework.

If it's not what You are looking for type in the equation solver your own equation and let us solve it.

Solution for -x^2+8x+31=0 equation:


Simplifying
-1x2 + 8x + 31 = 0

Reorder the terms:
31 + 8x + -1x2 = 0

Solving
31 + 8x + -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'.
-31 + -8x + x2 = 0

Move the constant term to the right:

Add '31' to each side of the equation.
-31 + -8x + 31 + x2 = 0 + 31

Reorder the terms:
-31 + 31 + -8x + x2 = 0 + 31

Combine like terms: -31 + 31 = 0
0 + -8x + x2 = 0 + 31
-8x + x2 = 0 + 31

Combine like terms: 0 + 31 = 31
-8x + x2 = 31

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

Add '16' to each side of the equation.
-8x + 16 + x2 = 31 + 16

Reorder the terms:
16 + -8x + x2 = 31 + 16

Combine like terms: 31 + 16 = 47
16 + -8x + x2 = 47

Factor a perfect square on the left side:
(x + -4)(x + -4) = 47

Calculate the square root of the right side: 6.8556546

Break this problem into two subproblems by setting 
(x + -4) equal to 6.8556546 and -6.8556546.

Subproblem 1

x + -4 = 6.8556546 Simplifying x + -4 = 6.8556546 Reorder the terms: -4 + x = 6.8556546 Solving -4 + x = 6.8556546 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '4' to each side of the equation. -4 + 4 + x = 6.8556546 + 4 Combine like terms: -4 + 4 = 0 0 + x = 6.8556546 + 4 x = 6.8556546 + 4 Combine like terms: 6.8556546 + 4 = 10.8556546 x = 10.8556546 Simplifying x = 10.8556546

Subproblem 2

x + -4 = -6.8556546 Simplifying x + -4 = -6.8556546 Reorder the terms: -4 + x = -6.8556546 Solving -4 + x = -6.8556546 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '4' to each side of the equation. -4 + 4 + x = -6.8556546 + 4 Combine like terms: -4 + 4 = 0 0 + x = -6.8556546 + 4 x = -6.8556546 + 4 Combine like terms: -6.8556546 + 4 = -2.8556546 x = -2.8556546 Simplifying x = -2.8556546

Solution

The solution to the problem is based on the solutions from the subproblems. x = {10.8556546, -2.8556546}

See similar equations:

| ln(2x+1)-ln(x-5)=1 | | cosx=-1.05 | | a^2-8a-20= | | b^3+5b^2-14b=0 | | 4x^2-150=5x^2+25x | | -5x+3=-27 | | m-13=3 | | 7h+2h-3=5 | | ysquared-14y+40=0 | | x^2-4+3= | | x^4-10x^2-3=0 | | Y/4=36 | | 1+7x=-62 | | 0.25x^2-4x+52=0 | | 82-u=261 | | -x^2+10x-28=0 | | y+5/8y=91 | | y+5/8=91 | | 3x^2-72x+450=0 | | log^2(7x+9)=2 | | -3/2x=3 | | 4x^2-90=5x^2+21x | | 6-3x=4+n | | 3i/-2+1 | | 7x+6=2x-4 | | 10x^2-45x=0 | | 188-6xsquared=38 | | 2+ysquared=18 | | 6/13x^2=39/2 | | 132=213-x | | 22x-12=-8x^2 | | 4xsquared+12=17xsquared |

Equations solver categories