r^2+9r-9=0

Simple and best practice solution for r^2+9r-9=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 r^2+9r-9=0 equation:


Simplifying
r2 + 9r + -9 = 0

Reorder the terms:
-9 + 9r + r2 = 0

Solving
-9 + 9r + r2 = 0

Solving for variable 'r'.

Begin completing the square.

Move the constant term to the right:

Add '9' to each side of the equation.
-9 + 9r + 9 + r2 = 0 + 9

Reorder the terms:
-9 + 9 + 9r + r2 = 0 + 9

Combine like terms: -9 + 9 = 0
0 + 9r + r2 = 0 + 9
9r + r2 = 0 + 9

Combine like terms: 0 + 9 = 9
9r + r2 = 9

The r term is 9r.  Take half its coefficient (4.5).
Square it (20.25) and add it to both sides.

Add '20.25' to each side of the equation.
9r + 20.25 + r2 = 9 + 20.25

Reorder the terms:
20.25 + 9r + r2 = 9 + 20.25

Combine like terms: 9 + 20.25 = 29.25
20.25 + 9r + r2 = 29.25

Factor a perfect square on the left side:
(r + 4.5)(r + 4.5) = 29.25

Calculate the square root of the right side: 5.408326913

Break this problem into two subproblems by setting 
(r + 4.5) equal to 5.408326913 and -5.408326913.

Subproblem 1

r + 4.5 = 5.408326913 Simplifying r + 4.5 = 5.408326913 Reorder the terms: 4.5 + r = 5.408326913 Solving 4.5 + r = 5.408326913 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '-4.5' to each side of the equation. 4.5 + -4.5 + r = 5.408326913 + -4.5 Combine like terms: 4.5 + -4.5 = 0.0 0.0 + r = 5.408326913 + -4.5 r = 5.408326913 + -4.5 Combine like terms: 5.408326913 + -4.5 = 0.908326913 r = 0.908326913 Simplifying r = 0.908326913

Subproblem 2

r + 4.5 = -5.408326913 Simplifying r + 4.5 = -5.408326913 Reorder the terms: 4.5 + r = -5.408326913 Solving 4.5 + r = -5.408326913 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '-4.5' to each side of the equation. 4.5 + -4.5 + r = -5.408326913 + -4.5 Combine like terms: 4.5 + -4.5 = 0.0 0.0 + r = -5.408326913 + -4.5 r = -5.408326913 + -4.5 Combine like terms: -5.408326913 + -4.5 = -9.908326913 r = -9.908326913 Simplifying r = -9.908326913

Solution

The solution to the problem is based on the solutions from the subproblems. r = {0.908326913, -9.908326913}

See similar equations:

| 6x+4=5x+40 | | p=2(99)+2(144) | | t-18=6 | | 9*25= | | 3n+.5=42 | | (27x+9)/3 | | 30x=750 | | -.05x^2+6x-5=0 | | x/-7=44 | | b*2-20b-41=3 | | 6-2(8-6)= | | 2x^2-28x+48=0 | | 500+x=16 | | k-8.2=12.5 | | -48=5u+2 | | 100/4-3i | | 12+(-10)= | | f(x)=3x^2-9x+2 | | -15+27y=25+7y | | g-4=13 | | 2(5-x)=2x-5+x | | 26x+323/35=17 | | 26x+323/35 | | 32-5v=3b+8 | | 6x^3+18x+x+3=0 | | 8/x+15/x^2=-1 | | 8-3+2-5-6= | | 2cos^2(4x-1)=0 | | 2cos^24x-1=0 | | 4y=6y-8 | | 7(x+1)=2(x-4) | | 2+15*9= |

Equations solver categories