8x^2+15x-11=0

Simple and best practice solution for 8x^2+15x-11=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 8x^2+15x-11=0 equation:


Simplifying
8x2 + 15x + -11 = 0

Reorder the terms:
-11 + 15x + 8x2 = 0

Solving
-11 + 15x + 8x2 = 0

Solving for variable 'x'.

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

Divide each side by '8'.
-1.375 + 1.875x + x2 = 0

Move the constant term to the right:

Add '1.375' to each side of the equation.
-1.375 + 1.875x + 1.375 + x2 = 0 + 1.375

Reorder the terms:
-1.375 + 1.375 + 1.875x + x2 = 0 + 1.375

Combine like terms: -1.375 + 1.375 = 0.000
0.000 + 1.875x + x2 = 0 + 1.375
1.875x + x2 = 0 + 1.375

Combine like terms: 0 + 1.375 = 1.375
1.875x + x2 = 1.375

The x term is 1.875x.  Take half its coefficient (0.9375).
Square it (0.87890625) and add it to both sides.

Add '0.87890625' to each side of the equation.
1.875x + 0.87890625 + x2 = 1.375 + 0.87890625

Reorder the terms:
0.87890625 + 1.875x + x2 = 1.375 + 0.87890625

Combine like terms: 1.375 + 0.87890625 = 2.25390625
0.87890625 + 1.875x + x2 = 2.25390625

Factor a perfect square on the left side:
(x + 0.9375)(x + 0.9375) = 2.25390625

Calculate the square root of the right side: 1.501301519

Break this problem into two subproblems by setting 
(x + 0.9375) equal to 1.501301519 and -1.501301519.

Subproblem 1

x + 0.9375 = 1.501301519 Simplifying x + 0.9375 = 1.501301519 Reorder the terms: 0.9375 + x = 1.501301519 Solving 0.9375 + x = 1.501301519 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-0.9375' to each side of the equation. 0.9375 + -0.9375 + x = 1.501301519 + -0.9375 Combine like terms: 0.9375 + -0.9375 = 0.0000 0.0000 + x = 1.501301519 + -0.9375 x = 1.501301519 + -0.9375 Combine like terms: 1.501301519 + -0.9375 = 0.563801519 x = 0.563801519 Simplifying x = 0.563801519

Subproblem 2

x + 0.9375 = -1.501301519 Simplifying x + 0.9375 = -1.501301519 Reorder the terms: 0.9375 + x = -1.501301519 Solving 0.9375 + x = -1.501301519 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-0.9375' to each side of the equation. 0.9375 + -0.9375 + x = -1.501301519 + -0.9375 Combine like terms: 0.9375 + -0.9375 = 0.0000 0.0000 + x = -1.501301519 + -0.9375 x = -1.501301519 + -0.9375 Combine like terms: -1.501301519 + -0.9375 = -2.438801519 x = -2.438801519 Simplifying x = -2.438801519

Solution

The solution to the problem is based on the solutions from the subproblems. x = {0.563801519, -2.438801519}

See similar equations:

| 8+x+8x^2+x^3= | | 5x+3x=18+2x | | Log(x)=3 | | 15x^2=10 | | 49+14z+z^2=0 | | r^2-10=3r | | 4m-5=5 | | 14x^2-23x=0 | | B-43.4=-120 | | -5x-6y=-15 | | 2v^2-20v=-21 | | 16+2x+16x^2+2x^3= | | 6x+3y=300 | | 12y+8y=0 | | 86=24 | | 9x^2-3x^2=6x+7x | | a+4=a^2+0.25 | | 6x+2y=16 | | -10y+15=5 | | 75x+45y=450 | | 18x^4-54x^2=0 | | x^4=27 | | 2+7=15 | | 4t^2=-17t | | 3+4g=30-5g | | 3e^2x+3=10 | | 9x^2-31x=51 | | x^2-50=5x | | y-x=-5 | | p=2k+2v | | -7x+23=2(x-2) | | 3x-0.4=x+1.4 |

Equations solver categories