x^2+11x=-21

Simple and best practice solution for x^2+11x=-21 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+11x=-21 equation:


Simplifying
x2 + 11x = -21

Reorder the terms:
11x + x2 = -21

Solving
11x + x2 = -21

Solving for variable 'x'.

Reorder the terms:
21 + 11x + x2 = -21 + 21

Combine like terms: -21 + 21 = 0
21 + 11x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-21' to each side of the equation.
21 + 11x + -21 + x2 = 0 + -21

Reorder the terms:
21 + -21 + 11x + x2 = 0 + -21

Combine like terms: 21 + -21 = 0
0 + 11x + x2 = 0 + -21
11x + x2 = 0 + -21

Combine like terms: 0 + -21 = -21
11x + x2 = -21

The x term is 11x.  Take half its coefficient (5.5).
Square it (30.25) and add it to both sides.

Add '30.25' to each side of the equation.
11x + 30.25 + x2 = -21 + 30.25

Reorder the terms:
30.25 + 11x + x2 = -21 + 30.25

Combine like terms: -21 + 30.25 = 9.25
30.25 + 11x + x2 = 9.25

Factor a perfect square on the left side:
(x + 5.5)(x + 5.5) = 9.25

Calculate the square root of the right side: 3.041381265

Break this problem into two subproblems by setting 
(x + 5.5) equal to 3.041381265 and -3.041381265.

Subproblem 1

x + 5.5 = 3.041381265 Simplifying x + 5.5 = 3.041381265 Reorder the terms: 5.5 + x = 3.041381265 Solving 5.5 + x = 3.041381265 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-5.5' to each side of the equation. 5.5 + -5.5 + x = 3.041381265 + -5.5 Combine like terms: 5.5 + -5.5 = 0.0 0.0 + x = 3.041381265 + -5.5 x = 3.041381265 + -5.5 Combine like terms: 3.041381265 + -5.5 = -2.458618735 x = -2.458618735 Simplifying x = -2.458618735

Subproblem 2

x + 5.5 = -3.041381265 Simplifying x + 5.5 = -3.041381265 Reorder the terms: 5.5 + x = -3.041381265 Solving 5.5 + x = -3.041381265 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-5.5' to each side of the equation. 5.5 + -5.5 + x = -3.041381265 + -5.5 Combine like terms: 5.5 + -5.5 = 0.0 0.0 + x = -3.041381265 + -5.5 x = -3.041381265 + -5.5 Combine like terms: -3.041381265 + -5.5 = -8.541381265 x = -8.541381265 Simplifying x = -8.541381265

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-2.458618735, -8.541381265}

See similar equations:

| 3g-2-g=8 | | 36*7= | | 2x-5=4y+25 | | X=6t-1.5y | | 2x+5=41 | | 32x=4 | | 36*71/42 | | (x+6)/(x-5)+1=11/(x-5) | | J=0.15+0.7 | | 3x-8-5x+2=5-8x-7+2x | | 18(1/3)2x=2 | | 3x-20=x+10 | | 3(x^2+8x+9)=0 | | 36x71/42 | | J=0.4+-0.25+0.7t | | 2.4=3m+4 | | 8-y=91 | | p(p+9)=-20 | | a-f=5 | | X=6+-1.5y | | -7(x+1)-17=27+5 | | 17=a-4 | | 5-x=3+4x+5 | | -3-8=4x+7-3x | | 139=6-7(1-4x) | | -16x^2+1000x+50=0 | | x^2+3x+8x+24= | | x^4-4x^3-21x^2=0 | | 2x^2-3x=62 | | -14x-20=-12x+90 | | 3x=8+3/2 | | 7(-4-7n)-7(6+3n)=70 |

Equations solver categories