r^2+19r-18=0

Simple and best practice solution for r^2+19r-18=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+19r-18=0 equation:


Simplifying
r2 + 19r + -18 = 0

Reorder the terms:
-18 + 19r + r2 = 0

Solving
-18 + 19r + r2 = 0

Solving for variable 'r'.

Begin completing the square.

Move the constant term to the right:

Add '18' to each side of the equation.
-18 + 19r + 18 + r2 = 0 + 18

Reorder the terms:
-18 + 18 + 19r + r2 = 0 + 18

Combine like terms: -18 + 18 = 0
0 + 19r + r2 = 0 + 18
19r + r2 = 0 + 18

Combine like terms: 0 + 18 = 18
19r + r2 = 18

The r term is 19r.  Take half its coefficient (9.5).
Square it (90.25) and add it to both sides.

Add '90.25' to each side of the equation.
19r + 90.25 + r2 = 18 + 90.25

Reorder the terms:
90.25 + 19r + r2 = 18 + 90.25

Combine like terms: 18 + 90.25 = 108.25
90.25 + 19r + r2 = 108.25

Factor a perfect square on the left side:
(r + 9.5)(r + 9.5) = 108.25

Calculate the square root of the right side: 10.404326023

Break this problem into two subproblems by setting 
(r + 9.5) equal to 10.404326023 and -10.404326023.

Subproblem 1

r + 9.5 = 10.404326023 Simplifying r + 9.5 = 10.404326023 Reorder the terms: 9.5 + r = 10.404326023 Solving 9.5 + r = 10.404326023 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '-9.5' to each side of the equation. 9.5 + -9.5 + r = 10.404326023 + -9.5 Combine like terms: 9.5 + -9.5 = 0.0 0.0 + r = 10.404326023 + -9.5 r = 10.404326023 + -9.5 Combine like terms: 10.404326023 + -9.5 = 0.904326023 r = 0.904326023 Simplifying r = 0.904326023

Subproblem 2

r + 9.5 = -10.404326023 Simplifying r + 9.5 = -10.404326023 Reorder the terms: 9.5 + r = -10.404326023 Solving 9.5 + r = -10.404326023 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '-9.5' to each side of the equation. 9.5 + -9.5 + r = -10.404326023 + -9.5 Combine like terms: 9.5 + -9.5 = 0.0 0.0 + r = -10.404326023 + -9.5 r = -10.404326023 + -9.5 Combine like terms: -10.404326023 + -9.5 = -19.904326023 r = -19.904326023 Simplifying r = -19.904326023

Solution

The solution to the problem is based on the solutions from the subproblems. r = {0.904326023, -19.904326023}

See similar equations:

| 11x-41=5x+1 | | r^2+19-18=0 | | X-9-6x= | | -4(6+n)+3=38 | | t(4t-1)=0 | | 49c^2-9p^2=0 | | 5(5u-3)=7(9-2u) | | 4r^2-12r+9=0 | | 144r^2-100=0 | | -36=2(x+4) | | 10y^2-23yz-5z^2=0 | | 3(2z+3)=5(8-5z) | | 6(6)-2(6)(2)=x | | 4c^2+13c-12=0 | | 6x^1+5x^2=60 | | -10=-5+x | | 77(2x-3)+3=24 | | 8c^3+26c^2-24=0 | | 3(8-6n)=41 | | 10c^2-29c+10=0 | | 3(3y+1)=7(13-5y) | | 3(3y+1)=(13-5y) | | 5b-5x=2b+ax | | 9x-45=4x-5 | | 6u^2+35u+6=0 | | 3c^2-24c+45=0 | | 3556-4577x-5667*3456=4567 | | 2(x+2)=5(11-3x) | | 36=6(x-5) | | w^2+5w-36=0 | | 9d+7=4d+27 | | 12x-21=5x |

Equations solver categories