x^2-18x-81=

Simple and best practice solution for x^2-18x-81= 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^2-18x-81= equation:


Simplifying
x2 + -18x + -81 = 0

Reorder the terms:
-81 + -18x + x2 = 0

Solving
-81 + -18x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '81' to each side of the equation.
-81 + -18x + 81 + x2 = 0 + 81

Reorder the terms:
-81 + 81 + -18x + x2 = 0 + 81

Combine like terms: -81 + 81 = 0
0 + -18x + x2 = 0 + 81
-18x + x2 = 0 + 81

Combine like terms: 0 + 81 = 81
-18x + x2 = 81

The x term is -18x.  Take half its coefficient (-9).
Square it (81) and add it to both sides.

Add '81' to each side of the equation.
-18x + 81 + x2 = 81 + 81

Reorder the terms:
81 + -18x + x2 = 81 + 81

Combine like terms: 81 + 81 = 162
81 + -18x + x2 = 162

Factor a perfect square on the left side:
(x + -9)(x + -9) = 162

Calculate the square root of the right side: 12.727922061

Break this problem into two subproblems by setting 
(x + -9) equal to 12.727922061 and -12.727922061.

Subproblem 1

x + -9 = 12.727922061 Simplifying x + -9 = 12.727922061 Reorder the terms: -9 + x = 12.727922061 Solving -9 + x = 12.727922061 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '9' to each side of the equation. -9 + 9 + x = 12.727922061 + 9 Combine like terms: -9 + 9 = 0 0 + x = 12.727922061 + 9 x = 12.727922061 + 9 Combine like terms: 12.727922061 + 9 = 21.727922061 x = 21.727922061 Simplifying x = 21.727922061

Subproblem 2

x + -9 = -12.727922061 Simplifying x + -9 = -12.727922061 Reorder the terms: -9 + x = -12.727922061 Solving -9 + x = -12.727922061 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '9' to each side of the equation. -9 + 9 + x = -12.727922061 + 9 Combine like terms: -9 + 9 = 0 0 + x = -12.727922061 + 9 x = -12.727922061 + 9 Combine like terms: -12.727922061 + 9 = -3.727922061 x = -3.727922061 Simplifying x = -3.727922061

Solution

The solution to the problem is based on the solutions from the subproblems. x = {21.727922061, -3.727922061}

See similar equations:

| y=-0.2x+4 | | 6(-3a+6)-5(6a-4)=-40 | | x+12=51 | | 21x+12=7x+12 | | x(x)=435 | | m=4(10)+2(5) | | x(2x-2)=35 | | 2n+10=-3n-5 | | 8x-2(10x-2)=20 | | 75+40x=y | | 23.75=18.75+2B | | X+3=-25 | | 5x+10=10x+10 | | -9n-8=10n-7 | | 2y-17y=72 | | 128=6(7+5x)-4 | | 8+4n=16 | | 3x-5=4+x-4x+2-3x | | S(x)=9x+5 | | 0=t^2+17t-30 | | 2.4(2x+3)=.1(2x+3) | | .03(6c-72)=-.9(c-6) | | -2(8x-5)=122 | | 2x+17x=42 | | 10x-1(5x-1)=60 | | 5x-19=2x+5+119 | | T-(-16)=4 | | -a+5(1-6a)=222 | | X-13=15x+12 | | X=15+-0.6y | | 24x+10+16x+90=180 | | -27=-6+3y |

Equations solver categories