11r^2-12r-13=0

Simple and best practice solution for 11r^2-12r-13=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 11r^2-12r-13=0 equation:


Simplifying
11r2 + -12r + -13 = 0

Reorder the terms:
-13 + -12r + 11r2 = 0

Solving
-13 + -12r + 11r2 = 0

Solving for variable 'r'.

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

Divide each side by '11'.
-1.181818182 + -1.090909091r + r2 = 0

Move the constant term to the right:

Add '1.181818182' to each side of the equation.
-1.181818182 + -1.090909091r + 1.181818182 + r2 = 0 + 1.181818182

Reorder the terms:
-1.181818182 + 1.181818182 + -1.090909091r + r2 = 0 + 1.181818182

Combine like terms: -1.181818182 + 1.181818182 = 0.000000000
0.000000000 + -1.090909091r + r2 = 0 + 1.181818182
-1.090909091r + r2 = 0 + 1.181818182

Combine like terms: 0 + 1.181818182 = 1.181818182
-1.090909091r + r2 = 1.181818182

The r term is -1.090909091r.  Take half its coefficient (-0.5454545455).
Square it (0.2975206612) and add it to both sides.

Add '0.2975206612' to each side of the equation.
-1.090909091r + 0.2975206612 + r2 = 1.181818182 + 0.2975206612

Reorder the terms:
0.2975206612 + -1.090909091r + r2 = 1.181818182 + 0.2975206612

Combine like terms: 1.181818182 + 0.2975206612 = 1.4793388432
0.2975206612 + -1.090909091r + r2 = 1.4793388432

Factor a perfect square on the left side:
(r + -0.5454545455)(r + -0.5454545455) = 1.4793388432

Calculate the square root of the right side: 1.216280742

Break this problem into two subproblems by setting 
(r + -0.5454545455) equal to 1.216280742 and -1.216280742.

Subproblem 1

r + -0.5454545455 = 1.216280742 Simplifying r + -0.5454545455 = 1.216280742 Reorder the terms: -0.5454545455 + r = 1.216280742 Solving -0.5454545455 + r = 1.216280742 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '0.5454545455' to each side of the equation. -0.5454545455 + 0.5454545455 + r = 1.216280742 + 0.5454545455 Combine like terms: -0.5454545455 + 0.5454545455 = 0.0000000000 0.0000000000 + r = 1.216280742 + 0.5454545455 r = 1.216280742 + 0.5454545455 Combine like terms: 1.216280742 + 0.5454545455 = 1.7617352875 r = 1.7617352875 Simplifying r = 1.7617352875

Subproblem 2

r + -0.5454545455 = -1.216280742 Simplifying r + -0.5454545455 = -1.216280742 Reorder the terms: -0.5454545455 + r = -1.216280742 Solving -0.5454545455 + r = -1.216280742 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '0.5454545455' to each side of the equation. -0.5454545455 + 0.5454545455 + r = -1.216280742 + 0.5454545455 Combine like terms: -0.5454545455 + 0.5454545455 = 0.0000000000 0.0000000000 + r = -1.216280742 + 0.5454545455 r = -1.216280742 + 0.5454545455 Combine like terms: -1.216280742 + 0.5454545455 = -0.6708261965 r = -0.6708261965 Simplifying r = -0.6708261965

Solution

The solution to the problem is based on the solutions from the subproblems. r = {1.7617352875, -0.6708261965}

See similar equations:

| 3(x)=-6 | | 9x+25=425 | | (1.247*10-3)/(2.9 | | 7(x-7)=35 | | -11=x-3/2 | | x*5+138=x*14-6 | | 2x^2+6=56 | | V=1(11-2x)(8.5-2x) | | Y-4=-.5(x-3) | | 4/1/2x=32 | | (3x-7)=11 | | V=1(11-2*1)(8.5-2*1) | | y=5sin(2x-45) | | V=(1)(11-2(1))(8.5-2(1)) | | t(n)=3n^2 | | 25+2.50x=42.50 | | 3(x+6)-2(1-x)=2 | | x=3x+70 | | Y+5=3y-31 | | 3y=x-30 | | 4v-16=12 | | sinx=.7547 | | 6y=5-2x | | 156=5(6w-9) | | 10y-3y=49 | | -4.4x=48.4 | | 6(2x-2)=54 | | 19a=26+6a | | y=(x^2)/(10)-3x | | -3/1/5-x=-16 | | (x^2)/(10)-3x | | 19x+10x= |

Equations solver categories