7x^2-2x-8=0

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


Simplifying
7x2 + -2x + -8 = 0

Reorder the terms:
-8 + -2x + 7x2 = 0

Solving
-8 + -2x + 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 + -0.2857142857x + x2 = 0

Move the constant term to the right:

Add '1.142857143' to each side of the equation.
-1.142857143 + -0.2857142857x + 1.142857143 + x2 = 0 + 1.142857143

Reorder the terms:
-1.142857143 + 1.142857143 + -0.2857142857x + x2 = 0 + 1.142857143

Combine like terms: -1.142857143 + 1.142857143 = 0.000000000
0.000000000 + -0.2857142857x + x2 = 0 + 1.142857143
-0.2857142857x + x2 = 0 + 1.142857143

Combine like terms: 0 + 1.142857143 = 1.142857143
-0.2857142857x + x2 = 1.142857143

The x term is -0.2857142857x.  Take half its coefficient (-0.1428571429).
Square it (0.02040816328) and add it to both sides.

Add '0.02040816328' to each side of the equation.
-0.2857142857x + 0.02040816328 + x2 = 1.142857143 + 0.02040816328

Reorder the terms:
0.02040816328 + -0.2857142857x + x2 = 1.142857143 + 0.02040816328

Combine like terms: 1.142857143 + 0.02040816328 = 1.16326530628
0.02040816328 + -0.2857142857x + x2 = 1.16326530628

Factor a perfect square on the left side:
(x + -0.1428571429)(x + -0.1428571429) = 1.16326530628

Calculate the square root of the right side: 1.078547777

Break this problem into two subproblems by setting 
(x + -0.1428571429) equal to 1.078547777 and -1.078547777.

Subproblem 1

x + -0.1428571429 = 1.078547777 Simplifying x + -0.1428571429 = 1.078547777 Reorder the terms: -0.1428571429 + x = 1.078547777 Solving -0.1428571429 + x = 1.078547777 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.1428571429' to each side of the equation. -0.1428571429 + 0.1428571429 + x = 1.078547777 + 0.1428571429 Combine like terms: -0.1428571429 + 0.1428571429 = 0.0000000000 0.0000000000 + x = 1.078547777 + 0.1428571429 x = 1.078547777 + 0.1428571429 Combine like terms: 1.078547777 + 0.1428571429 = 1.2214049199 x = 1.2214049199 Simplifying x = 1.2214049199

Subproblem 2

x + -0.1428571429 = -1.078547777 Simplifying x + -0.1428571429 = -1.078547777 Reorder the terms: -0.1428571429 + x = -1.078547777 Solving -0.1428571429 + x = -1.078547777 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.1428571429' to each side of the equation. -0.1428571429 + 0.1428571429 + x = -1.078547777 + 0.1428571429 Combine like terms: -0.1428571429 + 0.1428571429 = 0.0000000000 0.0000000000 + x = -1.078547777 + 0.1428571429 x = -1.078547777 + 0.1428571429 Combine like terms: -1.078547777 + 0.1428571429 = -0.9356906341 x = -0.9356906341 Simplifying x = -0.9356906341

Solution

The solution to the problem is based on the solutions from the subproblems. x = {1.2214049199, -0.9356906341}

See similar equations:

| -20+2x+12=4+x | | x+7+2x+6=13 | | 5m+29m+(-15m)= | | 3x^3+5x^2=27x+45 | | 2x-1+3x=14 | | x(x+2)(5x-1)=0 | | 4(4k+2)-8(k-1)=3(2k+3)-2 | | x-4=5-6x | | 6a+7+11=0 | | 3(2x-1)+3(x)=6(3) | | x-5+2x=-5+9x | | -7c+2=-33 | | 5+(5x+2)=9x-1 | | 28-12=4(x-7) | | 2x-3=-6x+4 | | -8x+9x+(-3x)= | | 3(10-5(-4x-5))=60x+105 | | -5(3t-5)+4t=2t-5 | | 5(-14+8)= | | 5(x-14+8)= | | 5x-10(x+1)=-5x+19 | | 5x^2-9x-36=0 | | 30(p+140)=100p | | 3x+5y=22 | | 12x+4=22 | | 9x+5=-10 | | 30(p+140)=p+140 | | -6n+11=-5n-15 | | 30(p+140)=p | | 6x^2+12x=15 | | x^2+3x-150=0 | | 30(p+140)= |

Equations solver categories