x^2-9x=40

Simple and best practice solution for x^2-9x=40 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^2-9x=40 equation:


Simplifying
x2 + -9x = 40

Reorder the terms:
-9x + x2 = 40

Solving
-9x + x2 = 40

Solving for variable 'x'.

Reorder the terms:
-40 + -9x + x2 = 40 + -40

Combine like terms: 40 + -40 = 0
-40 + -9x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '40' to each side of the equation.
-40 + -9x + 40 + x2 = 0 + 40

Reorder the terms:
-40 + 40 + -9x + x2 = 0 + 40

Combine like terms: -40 + 40 = 0
0 + -9x + x2 = 0 + 40
-9x + x2 = 0 + 40

Combine like terms: 0 + 40 = 40
-9x + x2 = 40

The x term is -9x.  Take half its coefficient (-4.5).
Square it (20.25) and add it to both sides.

Add '20.25' to each side of the equation.
-9x + 20.25 + x2 = 40 + 20.25

Reorder the terms:
20.25 + -9x + x2 = 40 + 20.25

Combine like terms: 40 + 20.25 = 60.25
20.25 + -9x + x2 = 60.25

Factor a perfect square on the left side:
(x + -4.5)(x + -4.5) = 60.25

Calculate the square root of the right side: 7.762087348

Break this problem into two subproblems by setting 
(x + -4.5) equal to 7.762087348 and -7.762087348.

Subproblem 1

x + -4.5 = 7.762087348 Simplifying x + -4.5 = 7.762087348 Reorder the terms: -4.5 + x = 7.762087348 Solving -4.5 + x = 7.762087348 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '4.5' to each side of the equation. -4.5 + 4.5 + x = 7.762087348 + 4.5 Combine like terms: -4.5 + 4.5 = 0.0 0.0 + x = 7.762087348 + 4.5 x = 7.762087348 + 4.5 Combine like terms: 7.762087348 + 4.5 = 12.262087348 x = 12.262087348 Simplifying x = 12.262087348

Subproblem 2

x + -4.5 = -7.762087348 Simplifying x + -4.5 = -7.762087348 Reorder the terms: -4.5 + x = -7.762087348 Solving -4.5 + x = -7.762087348 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '4.5' to each side of the equation. -4.5 + 4.5 + x = -7.762087348 + 4.5 Combine like terms: -4.5 + 4.5 = 0.0 0.0 + x = -7.762087348 + 4.5 x = -7.762087348 + 4.5 Combine like terms: -7.762087348 + 4.5 = -3.262087348 x = -3.262087348 Simplifying x = -3.262087348

Solution

The solution to the problem is based on the solutions from the subproblems. x = {12.262087348, -3.262087348}

See similar equations:

| 2x+x+25=360 | | (x-9)x(x+11)=0 | | 2x+x+25=50 | | d=0.35t+35 | | 2x+x+25=180 | | d=0.35+35 | | x^2-9-40=0 | | Log(7)(3x)+log(7)(2x-1)=log(7)(16x-10) | | (5x+7y)2+9x-2y=(8y+3)3 | | 4x+6+90=136 | | (3x+23)=(7x-45) | | 8x-(3x+7)=4-(5-4x) | | (6x^2-5)=0 | | 5p(p-4)-(2p-3)(3p+4)= | | 11.06=x-.20x | | 2(8y+3)=15+7y | | 26-y=4x | | 2x(3+-10)-4= | | x(x+20)=12000 | | 25b^3+110b^2-75b= | | 4/(2-i) | | 8x+3+7x+1+7x=180 | | 7h+2+3=20 | | 7n+84= | | 180-66= | | f(x)=2k^2-4k-4 | | z+(2xy+xy-y)=a | | ln(7x+62)=ln(5x+42) | | f(x)=k^2-4k-4 | | -3w+7=19 | | -x+7y=-4 | | 2xy+xy-y=z |

Equations solver categories