(20x^2)-18x-81=0

Simple and best practice solution for (20x^2)-18x-81=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 (20x^2)-18x-81=0 equation:


Simplifying
(20x2) + -18x + -81 = 0

Reorder the terms:
-81 + -18x + (20x2) = 0

Solving
-81 + -18x + (20x2) = 0

Solving for variable 'x'.

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

Divide each side by '20'.
-4.05 + -0.9x + x2 = 0

Move the constant term to the right:

Add '4.05' to each side of the equation.
-4.05 + -0.9x + 4.05 + x2 = 0 + 4.05

Reorder the terms:
-4.05 + 4.05 + -0.9x + x2 = 0 + 4.05

Combine like terms: -4.05 + 4.05 = 0.00
0.00 + -0.9x + x2 = 0 + 4.05
-0.9x + x2 = 0 + 4.05

Combine like terms: 0 + 4.05 = 4.05
-0.9x + x2 = 4.05

The x term is -0.9x.  Take half its coefficient (-0.45).
Square it (0.2025) and add it to both sides.

Add '0.2025' to each side of the equation.
-0.9x + 0.2025 + x2 = 4.05 + 0.2025

Reorder the terms:
0.2025 + -0.9x + x2 = 4.05 + 0.2025

Combine like terms: 4.05 + 0.2025 = 4.2525
0.2025 + -0.9x + x2 = 4.2525

Factor a perfect square on the left side:
((x) + -0.45)((x) + -0.45) = 4.2525

Calculate the square root of the right side: 2.062159063

Break this problem into two subproblems by setting 
((x) + -0.45) equal to 2.062159063 and -2.062159063.

Subproblem 1

(x) + -0.45 = 2.062159063 Simplifying (x) + -0.45 = 2.062159063 x + -0.45 = 2.062159063 Reorder the terms: -0.45 + x = 2.062159063 Solving -0.45 + x = 2.062159063 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.45' to each side of the equation. -0.45 + 0.45 + x = 2.062159063 + 0.45 Combine like terms: -0.45 + 0.45 = 0.00 0.00 + x = 2.062159063 + 0.45 x = 2.062159063 + 0.45 Combine like terms: 2.062159063 + 0.45 = 2.512159063 x = 2.512159063 Simplifying x = 2.512159063

Subproblem 2

(x) + -0.45 = -2.062159063 Simplifying (x) + -0.45 = -2.062159063 x + -0.45 = -2.062159063 Reorder the terms: -0.45 + x = -2.062159063 Solving -0.45 + x = -2.062159063 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.45' to each side of the equation. -0.45 + 0.45 + x = -2.062159063 + 0.45 Combine like terms: -0.45 + 0.45 = 0.00 0.00 + x = -2.062159063 + 0.45 x = -2.062159063 + 0.45 Combine like terms: -2.062159063 + 0.45 = -1.612159063 x = -1.612159063 Simplifying x = -1.612159063

Solution

The solution to the problem is based on the solutions from the subproblems. x = {2.512159063, -1.612159063}

See similar equations:

| 3.89(-y)=-24 | | X^2+1+6x=0 | | -8(y+5)=0 | | 9y=-9x+18 | | g(x)=esinx | | -4(8-6r)=-15 | | 4(x+7)=32-10x | | 20+20+7x+7x+90+5x+2y=360 | | 34+5y-10=16y-12-2y | | -1/5q=23 | | 6x-5(5x+4)=-115 | | X+x+7+5x=180 | | 2/5-1/9 | | x^2-2x-85=0 | | 1/4/12=x/15= | | 1/3x^2-(-27) | | 1/5q=23 | | -6x+7-5x=-92 | | 14n+6p-8n=18pforn | | -3(8p+6)-2(1-17p)=3(7+3p) | | 4x+2(2x+2)=5(x-1) | | 2*(2n-(n/3)) | | q=0.6p^2+8p | | 8p+9=15+7p | | 3.2x^2=7.2x | | P^2-8=-2p | | 2h-1/10-5/8 | | 123=8x+17y | | 3r^2x^2=4x^4 | | 2x(8-2)+(4-3)= | | 1050=150x+y | | Z/5-Z/1=8 |

Equations solver categories