2x^2+(-3)x-21=0

Simple and best practice solution for 2x^2+(-3)x-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 2x^2+(-3)x-21=0 equation:


Simplifying
2x2 + (-3) * x + -21 = 0

Reorder the terms:
-21 + -3x + 2x2 = 0

Solving
-21 + -3x + 2x2 = 0

Solving for variable 'x'.

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

Divide each side by '2'.
-10.5 + -1.5x + x2 = 0

Move the constant term to the right:

Add '10.5' to each side of the equation.
-10.5 + -1.5x + 10.5 + x2 = 0 + 10.5

Reorder the terms:
-10.5 + 10.5 + -1.5x + x2 = 0 + 10.5

Combine like terms: -10.5 + 10.5 = 0.0
0.0 + -1.5x + x2 = 0 + 10.5
-1.5x + x2 = 0 + 10.5

Combine like terms: 0 + 10.5 = 10.5
-1.5x + x2 = 10.5

The x term is -1.5x.  Take half its coefficient (-0.75).
Square it (0.5625) and add it to both sides.

Add '0.5625' to each side of the equation.
-1.5x + 0.5625 + x2 = 10.5 + 0.5625

Reorder the terms:
0.5625 + -1.5x + x2 = 10.5 + 0.5625

Combine like terms: 10.5 + 0.5625 = 11.0625
0.5625 + -1.5x + x2 = 11.0625

Factor a perfect square on the left side:
(x + -0.75)(x + -0.75) = 11.0625

Calculate the square root of the right side: 3.326033674

Break this problem into two subproblems by setting 
(x + -0.75) equal to 3.326033674 and -3.326033674.

Subproblem 1

x + -0.75 = 3.326033674 Simplifying x + -0.75 = 3.326033674 Reorder the terms: -0.75 + x = 3.326033674 Solving -0.75 + x = 3.326033674 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.75' to each side of the equation. -0.75 + 0.75 + x = 3.326033674 + 0.75 Combine like terms: -0.75 + 0.75 = 0.00 0.00 + x = 3.326033674 + 0.75 x = 3.326033674 + 0.75 Combine like terms: 3.326033674 + 0.75 = 4.076033674 x = 4.076033674 Simplifying x = 4.076033674

Subproblem 2

x + -0.75 = -3.326033674 Simplifying x + -0.75 = -3.326033674 Reorder the terms: -0.75 + x = -3.326033674 Solving -0.75 + x = -3.326033674 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.75' to each side of the equation. -0.75 + 0.75 + x = -3.326033674 + 0.75 Combine like terms: -0.75 + 0.75 = 0.00 0.00 + x = -3.326033674 + 0.75 x = -3.326033674 + 0.75 Combine like terms: -3.326033674 + 0.75 = -2.576033674 x = -2.576033674 Simplifying x = -2.576033674

Solution

The solution to the problem is based on the solutions from the subproblems. x = {4.076033674, -2.576033674}

See similar equations:

| 5x+1=12x+9 | | 3x^2-15=12x | | X^2-14x+21=0 | | 2x^2+11+9=0 | | -3+5y=-25 | | 3x^2-x+5 | | (2x^2)+7x+12=0 | | -2x+4y=24 | | 8-0.9k=8 | | 6x+5=45 | | 4(x-5)=3x-7 | | m^2-20m-300=0 | | x^2-17x-60 | | 24w^10*2u^6= | | 3x-3.8=x-3.0 | | 6y^2+7x-5= | | 4x-3y=-13 | | 4*w^9*u^4*6w*2*u^2= | | x+5y=-9 | | a*n=n^4*n-1 | | 12-12x=6x+45 | | 2x-1=14x+5 | | 20-3z=16 | | 11x+6y=47 | | 3x-4y=41 | | -x-6y=8 | | 7x-15y=1 | | 4x+6y-x+3y= | | 13y-8=15 | | 3a+a=48 | | 13x-15y=-2 | | 3-9c=-42 |

Equations solver categories