9x^2-14x-21=0

Simple and best practice solution for 9x^2-14x-21=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 9x^2-14x-21=0 equation:


Simplifying
9x2 + -14x + -21 = 0

Reorder the terms:
-21 + -14x + 9x2 = 0

Solving
-21 + -14x + 9x2 = 0

Solving for variable 'x'.

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

Divide each side by '9'.
-2.333333333 + -1.555555556x + x2 = 0

Move the constant term to the right:

Add '2.333333333' to each side of the equation.
-2.333333333 + -1.555555556x + 2.333333333 + x2 = 0 + 2.333333333

Reorder the terms:
-2.333333333 + 2.333333333 + -1.555555556x + x2 = 0 + 2.333333333

Combine like terms: -2.333333333 + 2.333333333 = 0.000000000
0.000000000 + -1.555555556x + x2 = 0 + 2.333333333
-1.555555556x + x2 = 0 + 2.333333333

Combine like terms: 0 + 2.333333333 = 2.333333333
-1.555555556x + x2 = 2.333333333

The x term is -1.555555556x.  Take half its coefficient (-0.777777778).
Square it (0.6049382720) and add it to both sides.

Add '0.6049382720' to each side of the equation.
-1.555555556x + 0.6049382720 + x2 = 2.333333333 + 0.6049382720

Reorder the terms:
0.6049382720 + -1.555555556x + x2 = 2.333333333 + 0.6049382720

Combine like terms: 2.333333333 + 0.6049382720 = 2.938271605
0.6049382720 + -1.555555556x + x2 = 2.938271605

Factor a perfect square on the left side:
(x + -0.777777778)(x + -0.777777778) = 2.938271605

Calculate the square root of the right side: 1.714138736

Break this problem into two subproblems by setting 
(x + -0.777777778) equal to 1.714138736 and -1.714138736.

Subproblem 1

x + -0.777777778 = 1.714138736 Simplifying x + -0.777777778 = 1.714138736 Reorder the terms: -0.777777778 + x = 1.714138736 Solving -0.777777778 + x = 1.714138736 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.777777778' to each side of the equation. -0.777777778 + 0.777777778 + x = 1.714138736 + 0.777777778 Combine like terms: -0.777777778 + 0.777777778 = 0.000000000 0.000000000 + x = 1.714138736 + 0.777777778 x = 1.714138736 + 0.777777778 Combine like terms: 1.714138736 + 0.777777778 = 2.491916514 x = 2.491916514 Simplifying x = 2.491916514

Subproblem 2

x + -0.777777778 = -1.714138736 Simplifying x + -0.777777778 = -1.714138736 Reorder the terms: -0.777777778 + x = -1.714138736 Solving -0.777777778 + x = -1.714138736 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.777777778' to each side of the equation. -0.777777778 + 0.777777778 + x = -1.714138736 + 0.777777778 Combine like terms: -0.777777778 + 0.777777778 = 0.000000000 0.000000000 + x = -1.714138736 + 0.777777778 x = -1.714138736 + 0.777777778 Combine like terms: -1.714138736 + 0.777777778 = -0.936360958 x = -0.936360958 Simplifying x = -0.936360958

Solution

The solution to the problem is based on the solutions from the subproblems. x = {2.491916514, -0.936360958}

See similar equations:

| 54-4x=5x+24 | | 2x+39i=14+3yi | | -3a-5=19 | | x(1)+3y=7 | | 5-3a=19 | | -30-9=8x+21 | | 5i-12=33 | | 2(3x+y)= | | 5(8y+4)= | | 4x+6-6=-6 | | -4+8p=44 | | 5y-1+y+29=6y+40-4y | | 1x-1+x/3=x/x-1 | | 4x+6-6=-6+6 | | 27-x=14 | | 4x+37=11x-3 | | 1/9+y=5/18 | | y/5=10/25 | | 6x-12=9x-27 | | 7.5/6 | | -2(x+1)+13x=12 | | (3x-5)+(2x+10)=4x+2 | | 2x+6-6=-4-6 | | Y/6=29 | | y-8=5(x+8) | | 5(4x-5)= | | 1+10x=46x | | -7(x+1)-18=34+4 | | 51-2x=12-10x | | (-8*-8)+3x=5x+4*4*4 | | 9ln(4x)=72 | | 1/2x^2-2x+3=0 |

Equations solver categories