7x^2-9x-8=0

Simple and best practice solution for 7x^2-9x-8=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 7x^2-9x-8=0 equation:


Simplifying
7x2 + -9x + -8 = 0

Reorder the terms:
-8 + -9x + 7x2 = 0

Solving
-8 + -9x + 7x2 = 0

Solving for variable 'x'.

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

Divide each side by '7'.
-1.142857143 + -1.285714286x + x2 = 0

Move the constant term to the right:

Add '1.142857143' to each side of the equation.
-1.142857143 + -1.285714286x + 1.142857143 + x2 = 0 + 1.142857143

Reorder the terms:
-1.142857143 + 1.142857143 + -1.285714286x + x2 = 0 + 1.142857143

Combine like terms: -1.142857143 + 1.142857143 = 0.000000000
0.000000000 + -1.285714286x + x2 = 0 + 1.142857143
-1.285714286x + x2 = 0 + 1.142857143

Combine like terms: 0 + 1.142857143 = 1.142857143
-1.285714286x + x2 = 1.142857143

The x term is -1.285714286x.  Take half its coefficient (-0.642857143).
Square it (0.4132653063) and add it to both sides.

Add '0.4132653063' to each side of the equation.
-1.285714286x + 0.4132653063 + x2 = 1.142857143 + 0.4132653063

Reorder the terms:
0.4132653063 + -1.285714286x + x2 = 1.142857143 + 0.4132653063

Combine like terms: 1.142857143 + 0.4132653063 = 1.5561224493
0.4132653063 + -1.285714286x + x2 = 1.5561224493

Factor a perfect square on the left side:
(x + -0.642857143)(x + -0.642857143) = 1.5561224493

Calculate the square root of the right side: 1.247446371

Break this problem into two subproblems by setting 
(x + -0.642857143) equal to 1.247446371 and -1.247446371.

Subproblem 1

x + -0.642857143 = 1.247446371 Simplifying x + -0.642857143 = 1.247446371 Reorder the terms: -0.642857143 + x = 1.247446371 Solving -0.642857143 + x = 1.247446371 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.642857143' to each side of the equation. -0.642857143 + 0.642857143 + x = 1.247446371 + 0.642857143 Combine like terms: -0.642857143 + 0.642857143 = 0.000000000 0.000000000 + x = 1.247446371 + 0.642857143 x = 1.247446371 + 0.642857143 Combine like terms: 1.247446371 + 0.642857143 = 1.890303514 x = 1.890303514 Simplifying x = 1.890303514

Subproblem 2

x + -0.642857143 = -1.247446371 Simplifying x + -0.642857143 = -1.247446371 Reorder the terms: -0.642857143 + x = -1.247446371 Solving -0.642857143 + x = -1.247446371 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.642857143' to each side of the equation. -0.642857143 + 0.642857143 + x = -1.247446371 + 0.642857143 Combine like terms: -0.642857143 + 0.642857143 = 0.000000000 0.000000000 + x = -1.247446371 + 0.642857143 x = -1.247446371 + 0.642857143 Combine like terms: -1.247446371 + 0.642857143 = -0.604589228 x = -0.604589228 Simplifying x = -0.604589228

Solution

The solution to the problem is based on the solutions from the subproblems. x = {1.890303514, -0.604589228}

See similar equations:

| sinx-0.5*(x)=0 | | sin(x)=0.703x | | 4x^4+21x^2-25=0 | | 4x^2+21x^2-25=0 | | n+27=43 | | n+26=44 | | X+2x+5x=72 | | 7+2+x=14 | | 713y-52+214y+32= | | 412y-62+315y+102= | | 2arctg= | | 3t^2-44t+121=0 | | 2tgx=0 | | 4+(4x)+2(x)=72 | | 2y-x=11 | | 4y+7=3x | | 2-10x+y^2-20y=-125 | | 2(x-1)+3x=16 | | 2a-1=a-8 | | x^3-3x^2+5x+45=0 | | x^3+5x^2+9x-45=0 | | x^3+3x^2+5x=45 | | 4x+(-7)=3x+(-1) | | 25=20x-4x | | 4.8=x-5.5 | | X-2.9=5.6 | | 2.2=0.11z | | x+6.9=-8.5 | | -6x-4=-3 | | -6-5=-28 | | p=.055x+.11y | | 0.05*a=1100 |

Equations solver categories