2r^2+15r+23=0

Simple and best practice solution for 2r^2+15r+23=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 2r^2+15r+23=0 equation:


Simplifying
2r2 + 15r + 23 = 0

Reorder the terms:
23 + 15r + 2r2 = 0

Solving
23 + 15r + 2r2 = 0

Solving for variable 'r'.

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

Divide each side by '2'.
11.5 + 7.5r + r2 = 0

Move the constant term to the right:

Add '-11.5' to each side of the equation.
11.5 + 7.5r + -11.5 + r2 = 0 + -11.5

Reorder the terms:
11.5 + -11.5 + 7.5r + r2 = 0 + -11.5

Combine like terms: 11.5 + -11.5 = 0.0
0.0 + 7.5r + r2 = 0 + -11.5
7.5r + r2 = 0 + -11.5

Combine like terms: 0 + -11.5 = -11.5
7.5r + r2 = -11.5

The r term is 7.5r.  Take half its coefficient (3.75).
Square it (14.0625) and add it to both sides.

Add '14.0625' to each side of the equation.
7.5r + 14.0625 + r2 = -11.5 + 14.0625

Reorder the terms:
14.0625 + 7.5r + r2 = -11.5 + 14.0625

Combine like terms: -11.5 + 14.0625 = 2.5625
14.0625 + 7.5r + r2 = 2.5625

Factor a perfect square on the left side:
(r + 3.75)(r + 3.75) = 2.5625

Calculate the square root of the right side: 1.600781059

Break this problem into two subproblems by setting 
(r + 3.75) equal to 1.600781059 and -1.600781059.

Subproblem 1

r + 3.75 = 1.600781059 Simplifying r + 3.75 = 1.600781059 Reorder the terms: 3.75 + r = 1.600781059 Solving 3.75 + r = 1.600781059 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '-3.75' to each side of the equation. 3.75 + -3.75 + r = 1.600781059 + -3.75 Combine like terms: 3.75 + -3.75 = 0.00 0.00 + r = 1.600781059 + -3.75 r = 1.600781059 + -3.75 Combine like terms: 1.600781059 + -3.75 = -2.149218941 r = -2.149218941 Simplifying r = -2.149218941

Subproblem 2

r + 3.75 = -1.600781059 Simplifying r + 3.75 = -1.600781059 Reorder the terms: 3.75 + r = -1.600781059 Solving 3.75 + r = -1.600781059 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '-3.75' to each side of the equation. 3.75 + -3.75 + r = -1.600781059 + -3.75 Combine like terms: 3.75 + -3.75 = 0.00 0.00 + r = -1.600781059 + -3.75 r = -1.600781059 + -3.75 Combine like terms: -1.600781059 + -3.75 = -5.350781059 r = -5.350781059 Simplifying r = -5.350781059

Solution

The solution to the problem is based on the solutions from the subproblems. r = {-2.149218941, -5.350781059}

See similar equations:

| 12r+60= | | u^2-3uv-108v^2=0 | | x^2+23x+22=0 | | g^2+4gh-60h^2=0 | | 5(2z-4)-7z=37 | | x(x-3)=1 | | 5[12-3(2-y)-2y]=2(1-y) | | 6x-7(x+3)=15 | | 8j-3(4j+6)=10 | | -6=-(x+7) | | 5[6-(5x-3)]+3x=0 | | x-4(2x+3)=16 | | 3x^2-900=0 | | 0.5(x-1)=1.0 | | 3-3(x+2)+2=2 | | a^2+2ab-15b^2=0 | | 5-5x=-3 | | 3.51-6.8x+1.11=22.3 | | 0.99y+2.22-0.09y=6.72 | | 25=7x+1-3x | | 6x-13=85 | | 2p-12=-8 | | -2(p-5)7p=-5 | | 4x^2-8x+9=0 | | 2x-8y=32 | | 3(8+42x)=12 | | 8x+2y=24 | | 3(8+42)=12 | | 6(y+9)=6(y-2) | | m^2-mn-42n^2=0 | | 2x^2+x+3=0 | | 2x-3=x+9 |

Equations solver categories