5x^2+21x-6=0

Simple and best practice solution for 5x^2+21x-6=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 5x^2+21x-6=0 equation:


Simplifying
5x2 + 21x + -6 = 0

Reorder the terms:
-6 + 21x + 5x2 = 0

Solving
-6 + 21x + 5x2 = 0

Solving for variable 'x'.

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

Divide each side by '5'.
-1.2 + 4.2x + x2 = 0

Move the constant term to the right:

Add '1.2' to each side of the equation.
-1.2 + 4.2x + 1.2 + x2 = 0 + 1.2

Reorder the terms:
-1.2 + 1.2 + 4.2x + x2 = 0 + 1.2

Combine like terms: -1.2 + 1.2 = 0.0
0.0 + 4.2x + x2 = 0 + 1.2
4.2x + x2 = 0 + 1.2

Combine like terms: 0 + 1.2 = 1.2
4.2x + x2 = 1.2

The x term is 4.2x.  Take half its coefficient (2.1).
Square it (4.41) and add it to both sides.

Add '4.41' to each side of the equation.
4.2x + 4.41 + x2 = 1.2 + 4.41

Reorder the terms:
4.41 + 4.2x + x2 = 1.2 + 4.41

Combine like terms: 1.2 + 4.41 = 5.61
4.41 + 4.2x + x2 = 5.61

Factor a perfect square on the left side:
(x + 2.1)(x + 2.1) = 5.61

Calculate the square root of the right side: 2.368543856

Break this problem into two subproblems by setting 
(x + 2.1) equal to 2.368543856 and -2.368543856.

Subproblem 1

x + 2.1 = 2.368543856 Simplifying x + 2.1 = 2.368543856 Reorder the terms: 2.1 + x = 2.368543856 Solving 2.1 + x = 2.368543856 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-2.1' to each side of the equation. 2.1 + -2.1 + x = 2.368543856 + -2.1 Combine like terms: 2.1 + -2.1 = 0.0 0.0 + x = 2.368543856 + -2.1 x = 2.368543856 + -2.1 Combine like terms: 2.368543856 + -2.1 = 0.268543856 x = 0.268543856 Simplifying x = 0.268543856

Subproblem 2

x + 2.1 = -2.368543856 Simplifying x + 2.1 = -2.368543856 Reorder the terms: 2.1 + x = -2.368543856 Solving 2.1 + x = -2.368543856 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-2.1' to each side of the equation. 2.1 + -2.1 + x = -2.368543856 + -2.1 Combine like terms: 2.1 + -2.1 = 0.0 0.0 + x = -2.368543856 + -2.1 x = -2.368543856 + -2.1 Combine like terms: -2.368543856 + -2.1 = -4.468543856 x = -4.468543856 Simplifying x = -4.468543856

Solution

The solution to the problem is based on the solutions from the subproblems. x = {0.268543856, -4.468543856}

See similar equations:

| x*4/9=12/15 | | 4(2x+6)=-44+4 | | M(9m+27)=792 | | 2/3x=7/0 | | 5p-8p-3+4p=-5 | | 15x=-50 | | 5p-(-5)=150 | | 7y-11=-3x+19 | | (5(9)+6)= | | 3(2l+1)=57 | | 3*x=1halb | | 5*x=1/3 | | w-5=-5/8 | | x=1212 | | 6x+32=-5(x-2) | | 2/9y-1/8=1/3 | | xmas=5 | | 7x+5=2x-4 | | 1.50x+2.00(12-x)=20 | | 8+15r-1=8r+19-5r | | .25x+.01y=62 | | 3*x=1/2 | | 3.5m+18= | | 0.6(x+60)+1.2x=117 | | 1.50+2.00(12-x)=20 | | 16x+3=16x-3 | | 5x-(11x+4)=25 | | 2(x+3)=-6x+2(x^2-2) | | -14n+10=-12n-12 | | 6-9x-2x+9=-5-x | | c=y+c | | y-55=8.5(x-0.5) |

Equations solver categories