2x^2+72x=-81

Simple and best practice solution for 2x^2+72x=-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 2x^2+72x=-81 equation:


Simplifying
2x2 + 72x = -81

Reorder the terms:
72x + 2x2 = -81

Solving
72x + 2x2 = -81

Solving for variable 'x'.

Reorder the terms:
81 + 72x + 2x2 = -81 + 81

Combine like terms: -81 + 81 = 0
81 + 72x + 2x2 = 0

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

Divide each side by '2'.
40.5 + 36x + x2 = 0

Move the constant term to the right:

Add '-40.5' to each side of the equation.
40.5 + 36x + -40.5 + x2 = 0 + -40.5

Reorder the terms:
40.5 + -40.5 + 36x + x2 = 0 + -40.5

Combine like terms: 40.5 + -40.5 = 0.0
0.0 + 36x + x2 = 0 + -40.5
36x + x2 = 0 + -40.5

Combine like terms: 0 + -40.5 = -40.5
36x + x2 = -40.5

The x term is 36x.  Take half its coefficient (18).
Square it (324) and add it to both sides.

Add '324' to each side of the equation.
36x + 324 + x2 = -40.5 + 324

Reorder the terms:
324 + 36x + x2 = -40.5 + 324

Combine like terms: -40.5 + 324 = 283.5
324 + 36x + x2 = 283.5

Factor a perfect square on the left side:
(x + 18)(x + 18) = 283.5

Calculate the square root of the right side: 16.83745824

Break this problem into two subproblems by setting 
(x + 18) equal to 16.83745824 and -16.83745824.

Subproblem 1

x + 18 = 16.83745824 Simplifying x + 18 = 16.83745824 Reorder the terms: 18 + x = 16.83745824 Solving 18 + x = 16.83745824 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-18' to each side of the equation. 18 + -18 + x = 16.83745824 + -18 Combine like terms: 18 + -18 = 0 0 + x = 16.83745824 + -18 x = 16.83745824 + -18 Combine like terms: 16.83745824 + -18 = -1.16254176 x = -1.16254176 Simplifying x = -1.16254176

Subproblem 2

x + 18 = -16.83745824 Simplifying x + 18 = -16.83745824 Reorder the terms: 18 + x = -16.83745824 Solving 18 + x = -16.83745824 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-18' to each side of the equation. 18 + -18 + x = -16.83745824 + -18 Combine like terms: 18 + -18 = 0 0 + x = -16.83745824 + -18 x = -16.83745824 + -18 Combine like terms: -16.83745824 + -18 = -34.83745824 x = -34.83745824 Simplifying x = -34.83745824

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-1.16254176, -34.83745824}

See similar equations:

| 8x^2+11x-7=0 | | 6x+20+4x=180 | | 12x+8y=40 | | X+132=(x+2) | | (-8)+12e=(-20) | | y^2-28y+132=0 | | 90=x+30-2y | | x=2x+6 | | 3v-6v=7-13 | | 6x+20=4x | | 2(6v+2)=-(-8-7v)+8v | | 16x^2+72x=-81 | | 3x^2+5x=7 | | 3x-3=x-1 | | 2y-2=4-y | | x^3-2x+1=0 | | 7-4x=2x+27 | | 2x-2=5x+16 | | (-4)y-9=15 | | 6x-3=5x | | (-4)y-9=14 | | 5x=110 | | 16x^2+56x=-49 | | 12w-4=8w+12 | | X^3+3x^2-14x-20=0 | | 4x-2x+1=7 | | 2x+6=3x-6 | | -8=-1(x+4) | | 5z^2+12z+4= | | 2x=-y+5 | | 123+456x-789*10=180 | | (x+2)(x-5)=0 |

Equations solver categories