x^2+21x+-77=0

Simple and best practice solution for x^2+21x+-77=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 x^2+21x+-77=0 equation:


Simplifying
x2 + 21x + -77 = 0

Reorder the terms:
-77 + 21x + x2 = 0

Solving
-77 + 21x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '77' to each side of the equation.
-77 + 21x + 77 + x2 = 0 + 77

Reorder the terms:
-77 + 77 + 21x + x2 = 0 + 77

Combine like terms: -77 + 77 = 0
0 + 21x + x2 = 0 + 77
21x + x2 = 0 + 77

Combine like terms: 0 + 77 = 77
21x + x2 = 77

The x term is 21x.  Take half its coefficient (10.5).
Square it (110.25) and add it to both sides.

Add '110.25' to each side of the equation.
21x + 110.25 + x2 = 77 + 110.25

Reorder the terms:
110.25 + 21x + x2 = 77 + 110.25

Combine like terms: 77 + 110.25 = 187.25
110.25 + 21x + x2 = 187.25

Factor a perfect square on the left side:
(x + 10.5)(x + 10.5) = 187.25

Calculate the square root of the right side: 13.683932183

Break this problem into two subproblems by setting 
(x + 10.5) equal to 13.683932183 and -13.683932183.

Subproblem 1

x + 10.5 = 13.683932183 Simplifying x + 10.5 = 13.683932183 Reorder the terms: 10.5 + x = 13.683932183 Solving 10.5 + x = 13.683932183 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-10.5' to each side of the equation. 10.5 + -10.5 + x = 13.683932183 + -10.5 Combine like terms: 10.5 + -10.5 = 0.0 0.0 + x = 13.683932183 + -10.5 x = 13.683932183 + -10.5 Combine like terms: 13.683932183 + -10.5 = 3.183932183 x = 3.183932183 Simplifying x = 3.183932183

Subproblem 2

x + 10.5 = -13.683932183 Simplifying x + 10.5 = -13.683932183 Reorder the terms: 10.5 + x = -13.683932183 Solving 10.5 + x = -13.683932183 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-10.5' to each side of the equation. 10.5 + -10.5 + x = -13.683932183 + -10.5 Combine like terms: 10.5 + -10.5 = 0.0 0.0 + x = -13.683932183 + -10.5 x = -13.683932183 + -10.5 Combine like terms: -13.683932183 + -10.5 = -24.183932183 x = -24.183932183 Simplifying x = -24.183932183

Solution

The solution to the problem is based on the solutions from the subproblems. x = {3.183932183, -24.183932183}

See similar equations:

| 0.4x+13.8=x-7.86 | | 3(a+17)= | | 12x+12y+5z=1355 | | .208=(x-23.8)/x | | (1/2(x)^(5/2)=16 | | X-23.8=.208X | | (y+1)(y-1)=3 | | 21/2.54 | | -2y+14=-6y-14 | | 2x^2+10x+6=-2 | | 30(p+20)=750 | | x^2+1.2x-0.5=0 | | 6x^2y+18x=0 | | x^2+1.2x+0.5=0 | | 11x=15x^2 | | .2(x+2)=-9 | | 2(3x-4.1)=8x-8.2 | | x^2=13/2 | | x^2=36/4 | | 3x+2b=3b-7x | | .21=(x-23.8)/x | | 5/6.5 | | (3x-5)(8x-2)=(6x+10)(4x+6) | | 2x+2=156 | | 3x/5-1=2 | | x=3(x-26) | | -9=-11=b/8 | | 9(-v-z)= | | (-2+6i)(-2+6i)= | | 1x-1/7x=18 | | -1/4y-1=-14.5 | | Z^2+33-14z= |

Equations solver categories