r^2+5r+84=0

Simple and best practice solution for r^2+5r+84=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+5r+84=0 equation:


Simplifying
r2 + 5r + 84 = 0

Reorder the terms:
84 + 5r + r2 = 0

Solving
84 + 5r + r2 = 0

Solving for variable 'r'.

Begin completing the square.

Move the constant term to the right:

Add '-84' to each side of the equation.
84 + 5r + -84 + r2 = 0 + -84

Reorder the terms:
84 + -84 + 5r + r2 = 0 + -84

Combine like terms: 84 + -84 = 0
0 + 5r + r2 = 0 + -84
5r + r2 = 0 + -84

Combine like terms: 0 + -84 = -84
5r + r2 = -84

The r term is 5r.  Take half its coefficient (2.5).
Square it (6.25) and add it to both sides.

Add '6.25' to each side of the equation.
5r + 6.25 + r2 = -84 + 6.25

Reorder the terms:
6.25 + 5r + r2 = -84 + 6.25

Combine like terms: -84 + 6.25 = -77.75
6.25 + 5r + r2 = -77.75

Factor a perfect square on the left side:
(r + 2.5)(r + 2.5) = -77.75

Can't calculate square root of the right side.

The solution to this equation could not be determined.

See similar equations:

| 5n-15=n+20 | | 0.27p=-2 | | 14-8x=70 | | (2x^2-3x+1)(2x^2+5x+1)=9x^2 | | 3x+5y+2-3y-7x-5= | | 3x+35=95 | | 67-6x=3x+15 | | 10n+17=3n+51 | | 519-x=637 | | 224+x=199 | | r^2+2r-25=0 | | 7-9x=162-44x | | x-125=-421 | | x-125=421 | | 37.6x+15.1-21.4x+16.1= | | 5x+22=12-48 | | 7r+7=49 | | 71.97(c)=37.52 | | 9x+13=67 | | 3x^2+7x+2=2x-6 | | 3x=13-2y | | 109.49=c/(1-m) | | 8x-1+4x+7=90 | | 8x-1=90 | | 9p-4=31 | | (3x+12)(x^2-11x+24)(x^3-125)=0 | | 2x^3-7x^2+6x=0 | | 4x-9+7x=31 | | 7x+11=4x+2 | | 21b^2-12b+14b-8=0 | | 2x2/5 | | 56=7/2w |

Equations solver categories