-x^2+40x-80=0

Simple and best practice solution for -x^2+40x-80=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+40x-80=0 equation:


Simplifying
-1x2 + 40x + -80 = 0

Reorder the terms:
-80 + 40x + -1x2 = 0

Solving
-80 + 40x + -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'.
80 + -40x + x2 = 0

Move the constant term to the right:

Add '-80' to each side of the equation.
80 + -40x + -80 + x2 = 0 + -80

Reorder the terms:
80 + -80 + -40x + x2 = 0 + -80

Combine like terms: 80 + -80 = 0
0 + -40x + x2 = 0 + -80
-40x + x2 = 0 + -80

Combine like terms: 0 + -80 = -80
-40x + x2 = -80

The x term is -40x.  Take half its coefficient (-20).
Square it (400) and add it to both sides.

Add '400' to each side of the equation.
-40x + 400 + x2 = -80 + 400

Reorder the terms:
400 + -40x + x2 = -80 + 400

Combine like terms: -80 + 400 = 320
400 + -40x + x2 = 320

Factor a perfect square on the left side:
(x + -20)(x + -20) = 320

Calculate the square root of the right side: 17.88854382

Break this problem into two subproblems by setting 
(x + -20) equal to 17.88854382 and -17.88854382.

Subproblem 1

x + -20 = 17.88854382 Simplifying x + -20 = 17.88854382 Reorder the terms: -20 + x = 17.88854382 Solving -20 + x = 17.88854382 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '20' to each side of the equation. -20 + 20 + x = 17.88854382 + 20 Combine like terms: -20 + 20 = 0 0 + x = 17.88854382 + 20 x = 17.88854382 + 20 Combine like terms: 17.88854382 + 20 = 37.88854382 x = 37.88854382 Simplifying x = 37.88854382

Subproblem 2

x + -20 = -17.88854382 Simplifying x + -20 = -17.88854382 Reorder the terms: -20 + x = -17.88854382 Solving -20 + x = -17.88854382 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '20' to each side of the equation. -20 + 20 + x = -17.88854382 + 20 Combine like terms: -20 + 20 = 0 0 + x = -17.88854382 + 20 x = -17.88854382 + 20 Combine like terms: -17.88854382 + 20 = 2.11145618 x = 2.11145618 Simplifying x = 2.11145618

Solution

The solution to the problem is based on the solutions from the subproblems. x = {37.88854382, 2.11145618}

See similar equations:

| Lnx^2-2lnx-3=0 | | (9+3i)+(x+yi)=(-8-6i) | | 4x+2y=842 | | 9+0.75x=0.87x-10 | | 2(x-3)+4x=-(-x+1) | | 3(1-2x)=-9 | | -17r=47 | | -84=3m | | 6+9x+5=4x-6+9x*3 | | 15x+2=x-15 | | 36x-4x^2= | | 4y+24+2x+5=180 | | 8000=s | | 0.02+0.01(50000-x)=88 | | -7-6y=-41-8x | | 4y+24+7x-15=180 | | 3(1-2x)-4=-13 | | 4y+24+7y+3=180 | | m-12=n | | 25+50x=425 | | 55x+5y=-25 | | 6(y-1)=3y+6 | | 4x-5y=29 | | 3z-2(z-9)=2+2z | | (11-4n)=3 | | 4(3-t)-(2-2t)=1 | | 1.5=.5v-0.2857142857 | | 3z+2(6-z)=-(z-3)+1 | | 3z+s(6-z)=-(z-3)+1 | | 2x(7+3)-8= | | 4z+3(5-z)=-(z-1)+10 | | 0.2x-7.5(x-1)=44 |

Equations solver categories