r^2+18r+69=31

Simple and best practice solution for r^2+18r+69=31 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 r^2+18r+69=31 equation:


Simplifying
r2 + 18r + 69 = 31

Reorder the terms:
69 + 18r + r2 = 31

Solving
69 + 18r + r2 = 31

Solving for variable 'r'.

Reorder the terms:
69 + -31 + 18r + r2 = 31 + -31

Combine like terms: 69 + -31 = 38
38 + 18r + r2 = 31 + -31

Combine like terms: 31 + -31 = 0
38 + 18r + r2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-38' to each side of the equation.
38 + 18r + -38 + r2 = 0 + -38

Reorder the terms:
38 + -38 + 18r + r2 = 0 + -38

Combine like terms: 38 + -38 = 0
0 + 18r + r2 = 0 + -38
18r + r2 = 0 + -38

Combine like terms: 0 + -38 = -38
18r + r2 = -38

The r term is 18r.  Take half its coefficient (9).
Square it (81) and add it to both sides.

Add '81' to each side of the equation.
18r + 81 + r2 = -38 + 81

Reorder the terms:
81 + 18r + r2 = -38 + 81

Combine like terms: -38 + 81 = 43
81 + 18r + r2 = 43

Factor a perfect square on the left side:
(r + 9)(r + 9) = 43

Calculate the square root of the right side: 6.557438524

Break this problem into two subproblems by setting 
(r + 9) equal to 6.557438524 and -6.557438524.

Subproblem 1

r + 9 = 6.557438524 Simplifying r + 9 = 6.557438524 Reorder the terms: 9 + r = 6.557438524 Solving 9 + r = 6.557438524 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '-9' to each side of the equation. 9 + -9 + r = 6.557438524 + -9 Combine like terms: 9 + -9 = 0 0 + r = 6.557438524 + -9 r = 6.557438524 + -9 Combine like terms: 6.557438524 + -9 = -2.442561476 r = -2.442561476 Simplifying r = -2.442561476

Subproblem 2

r + 9 = -6.557438524 Simplifying r + 9 = -6.557438524 Reorder the terms: 9 + r = -6.557438524 Solving 9 + r = -6.557438524 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '-9' to each side of the equation. 9 + -9 + r = -6.557438524 + -9 Combine like terms: 9 + -9 = 0 0 + r = -6.557438524 + -9 r = -6.557438524 + -9 Combine like terms: -6.557438524 + -9 = -15.557438524 r = -15.557438524 Simplifying r = -15.557438524

Solution

The solution to the problem is based on the solutions from the subproblems. r = {-2.442561476, -15.557438524}

See similar equations:

| 7x^2-38x=15 | | -5(c+4)+3c=-2(1+5c)+6 | | 45=-7x+10 | | g(x-2)=2x^2-4x | | 47.18x-12-3xy+2y+15xz-10z= | | 15*15*15= | | 2v^2+v^2=3 | | 6(-3+5p)=-18-2p | | 8c-6=4 | | X-1/2=7/10 | | w^2+6w+15=53 | | (3y+11)=(4x-22) | | (X-4.9)+0.5x=x-4 | | 10y^2+27y-21=0 | | 7=q+9 | | 2x(x+3)2x(x+3)=24 | | 6(3y-2)=2y-6y+7 | | y/5-2=1 | | u^2-8u+28=41 | | 3/4*x=-2 | | 9/5(-20) | | x/3-9-14 | | .75*x=-2 | | 4-3n=48 | | 2x^2-7x+36=0 | | s^2-6s-7=0 | | 2/3y-1/2(5)=-1 | | -5x-1=-25 | | solving(3x-1)(5x-2)=0 | | h^2-8h+31=62 | | k^2+8k+30=72 | | k^2+8k+30=37 |

Equations solver categories