3x^2+9x=8

Simple and best practice solution for 3x^2+9x=8 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 3x^2+9x=8 equation:


Simplifying
3x2 + 9x = 8

Reorder the terms:
9x + 3x2 = 8

Solving
9x + 3x2 = 8

Solving for variable 'x'.

Reorder the terms:
-8 + 9x + 3x2 = 8 + -8

Combine like terms: 8 + -8 = 0
-8 + 9x + 3x2 = 0

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

Divide each side by '3'.
-2.666666667 + 3x + x2 = 0

Move the constant term to the right:

Add '2.666666667' to each side of the equation.
-2.666666667 + 3x + 2.666666667 + x2 = 0 + 2.666666667

Reorder the terms:
-2.666666667 + 2.666666667 + 3x + x2 = 0 + 2.666666667

Combine like terms: -2.666666667 + 2.666666667 = 0.000000000
0.000000000 + 3x + x2 = 0 + 2.666666667
3x + x2 = 0 + 2.666666667

Combine like terms: 0 + 2.666666667 = 2.666666667
3x + x2 = 2.666666667

The x term is 3x.  Take half its coefficient (1.5).
Square it (2.25) and add it to both sides.

Add '2.25' to each side of the equation.
3x + 2.25 + x2 = 2.666666667 + 2.25

Reorder the terms:
2.25 + 3x + x2 = 2.666666667 + 2.25

Combine like terms: 2.666666667 + 2.25 = 4.916666667
2.25 + 3x + x2 = 4.916666667

Factor a perfect square on the left side:
(x + 1.5)(x + 1.5) = 4.916666667

Calculate the square root of the right side: 2.217355783

Break this problem into two subproblems by setting 
(x + 1.5) equal to 2.217355783 and -2.217355783.

Subproblem 1

x + 1.5 = 2.217355783 Simplifying x + 1.5 = 2.217355783 Reorder the terms: 1.5 + x = 2.217355783 Solving 1.5 + x = 2.217355783 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-1.5' to each side of the equation. 1.5 + -1.5 + x = 2.217355783 + -1.5 Combine like terms: 1.5 + -1.5 = 0.0 0.0 + x = 2.217355783 + -1.5 x = 2.217355783 + -1.5 Combine like terms: 2.217355783 + -1.5 = 0.717355783 x = 0.717355783 Simplifying x = 0.717355783

Subproblem 2

x + 1.5 = -2.217355783 Simplifying x + 1.5 = -2.217355783 Reorder the terms: 1.5 + x = -2.217355783 Solving 1.5 + x = -2.217355783 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-1.5' to each side of the equation. 1.5 + -1.5 + x = -2.217355783 + -1.5 Combine like terms: 1.5 + -1.5 = 0.0 0.0 + x = -2.217355783 + -1.5 x = -2.217355783 + -1.5 Combine like terms: -2.217355783 + -1.5 = -3.717355783 x = -3.717355783 Simplifying x = -3.717355783

Solution

The solution to the problem is based on the solutions from the subproblems. x = {0.717355783, -3.717355783}

See similar equations:

| 4x=10+4x-5 | | 4p-5+p=75p+2 | | 7+1.25x=43.25 | | 9x+16=15x-8 | | 5(l-4)=3(1+2) | | 4(p-6)-5(1+6p)=23 | | 7.5=y | | 3(y-10)+1=.5(y-8) | | -4x-4(5x-8)=152 | | 4*4*4+(-2*-2*-2*-2)= | | -(x-4)+y=5 | | 4x+2x+7=5x+7 | | x/2xy=0 | | (3x+4)-2(x-4)+5x= | | 39-5x=11+9x | | -9=81-45t | | 4x+1=ax | | -7y+8=-7y-4 | | 2x^3+3x^2-x-4= | | 2x^3+3x^2-x-4=0 | | (2x-3)(4x+2)=3 | | 3x+11+4x-21=180 | | -4x-36=-8 | | 6x-5(-x-10)=171 | | 7y-14x=14 | | X-45=85 | | u=3+7 | | 3x-4-4x=-8 | | -8=3p-14-2p | | 8d+2d-3d-6-5d=0 | | c=13.4r | | a=bx+t+c |

Equations solver categories