10x^2-18x-21=0

Simple and best practice solution for 10x^2-18x-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 10x^2-18x-21=0 equation:


Simplifying
10x2 + -18x + -21 = 0

Reorder the terms:
-21 + -18x + 10x2 = 0

Solving
-21 + -18x + 10x2 = 0

Solving for variable 'x'.

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

Divide each side by '10'.
-2.1 + -1.8x + x2 = 0

Move the constant term to the right:

Add '2.1' to each side of the equation.
-2.1 + -1.8x + 2.1 + x2 = 0 + 2.1

Reorder the terms:
-2.1 + 2.1 + -1.8x + x2 = 0 + 2.1

Combine like terms: -2.1 + 2.1 = 0.0
0.0 + -1.8x + x2 = 0 + 2.1
-1.8x + x2 = 0 + 2.1

Combine like terms: 0 + 2.1 = 2.1
-1.8x + x2 = 2.1

The x term is -1.8x.  Take half its coefficient (-0.9).
Square it (0.81) and add it to both sides.

Add '0.81' to each side of the equation.
-1.8x + 0.81 + x2 = 2.1 + 0.81

Reorder the terms:
0.81 + -1.8x + x2 = 2.1 + 0.81

Combine like terms: 2.1 + 0.81 = 2.91
0.81 + -1.8x + x2 = 2.91

Factor a perfect square on the left side:
(x + -0.9)(x + -0.9) = 2.91

Calculate the square root of the right side: 1.705872211

Break this problem into two subproblems by setting 
(x + -0.9) equal to 1.705872211 and -1.705872211.

Subproblem 1

x + -0.9 = 1.705872211 Simplifying x + -0.9 = 1.705872211 Reorder the terms: -0.9 + x = 1.705872211 Solving -0.9 + x = 1.705872211 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.9' to each side of the equation. -0.9 + 0.9 + x = 1.705872211 + 0.9 Combine like terms: -0.9 + 0.9 = 0.0 0.0 + x = 1.705872211 + 0.9 x = 1.705872211 + 0.9 Combine like terms: 1.705872211 + 0.9 = 2.605872211 x = 2.605872211 Simplifying x = 2.605872211

Subproblem 2

x + -0.9 = -1.705872211 Simplifying x + -0.9 = -1.705872211 Reorder the terms: -0.9 + x = -1.705872211 Solving -0.9 + x = -1.705872211 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.9' to each side of the equation. -0.9 + 0.9 + x = -1.705872211 + 0.9 Combine like terms: -0.9 + 0.9 = 0.0 0.0 + x = -1.705872211 + 0.9 x = -1.705872211 + 0.9 Combine like terms: -1.705872211 + 0.9 = -0.805872211 x = -0.805872211 Simplifying x = -0.805872211

Solution

The solution to the problem is based on the solutions from the subproblems. x = {2.605872211, -0.805872211}

See similar equations:

| -5(6x-2)= | | 4+2=y | | 9x-2=3x+38 | | 40x-2x^2=0 | | r+9.45=12 | | 12x+8+3x-4= | | 3x+5=51 | | y=90+14x | | 0.4x-3=2.2 | | 5x+5(6x+7)= | | 4(x+6)=3(8+9x) | | 17x+4=8x+12 | | -4(x+3)=-12-3x | | 2(6x-3)=0 | | 1122=6h | | 0.3b=27.9 | | -30+4x=-3(x+3) | | 9a=7c | | g+2g+3-4= | | 20.25=x^2+2x+1 | | 2(x-5)=3x-6 | | =x^2+100x+2500 | | -12-x=2x+6 | | 18y=-6x | | h+28=52 | | -2x+3=x+6 | | 12+3t=6 | | 6(-1x-5)=-18 | | 7m-5+3m+8= | | 6(2x+8)=168 | | -5(6+7x)=-380 | | 7x+3y=180 |

Equations solver categories