k^2+9k+15=0

Simple and best practice solution for k^2+9k+15=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 k^2+9k+15=0 equation:


Simplifying
k2 + 9k + 15 = 0

Reorder the terms:
15 + 9k + k2 = 0

Solving
15 + 9k + k2 = 0

Solving for variable 'k'.

Begin completing the square.

Move the constant term to the right:

Add '-15' to each side of the equation.
15 + 9k + -15 + k2 = 0 + -15

Reorder the terms:
15 + -15 + 9k + k2 = 0 + -15

Combine like terms: 15 + -15 = 0
0 + 9k + k2 = 0 + -15
9k + k2 = 0 + -15

Combine like terms: 0 + -15 = -15
9k + k2 = -15

The k term is 9k.  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.
9k + 20.25 + k2 = -15 + 20.25

Reorder the terms:
20.25 + 9k + k2 = -15 + 20.25

Combine like terms: -15 + 20.25 = 5.25
20.25 + 9k + k2 = 5.25

Factor a perfect square on the left side:
(k + 4.5)(k + 4.5) = 5.25

Calculate the square root of the right side: 2.291287847

Break this problem into two subproblems by setting 
(k + 4.5) equal to 2.291287847 and -2.291287847.

Subproblem 1

k + 4.5 = 2.291287847 Simplifying k + 4.5 = 2.291287847 Reorder the terms: 4.5 + k = 2.291287847 Solving 4.5 + k = 2.291287847 Solving for variable 'k'. Move all terms containing k to the left, all other terms to the right. Add '-4.5' to each side of the equation. 4.5 + -4.5 + k = 2.291287847 + -4.5 Combine like terms: 4.5 + -4.5 = 0.0 0.0 + k = 2.291287847 + -4.5 k = 2.291287847 + -4.5 Combine like terms: 2.291287847 + -4.5 = -2.208712153 k = -2.208712153 Simplifying k = -2.208712153

Subproblem 2

k + 4.5 = -2.291287847 Simplifying k + 4.5 = -2.291287847 Reorder the terms: 4.5 + k = -2.291287847 Solving 4.5 + k = -2.291287847 Solving for variable 'k'. Move all terms containing k to the left, all other terms to the right. Add '-4.5' to each side of the equation. 4.5 + -4.5 + k = -2.291287847 + -4.5 Combine like terms: 4.5 + -4.5 = 0.0 0.0 + k = -2.291287847 + -4.5 k = -2.291287847 + -4.5 Combine like terms: -2.291287847 + -4.5 = -6.791287847 k = -6.791287847 Simplifying k = -6.791287847

Solution

The solution to the problem is based on the solutions from the subproblems. k = {-2.208712153, -6.791287847}

See similar equations:

| (4x-5)*(8x^2+2x-4)= | | 0.50x+0.10(70)=0.25(108) | | z/2=-4 | | 19x^2-18=139 | | 21k=-102 | | 21k=25 | | 1-3p-3=17 | | .3m+5=35 | | 3t-6=-1.5 | | x^4+-4x^2+-4x^2+16= | | B/-6=-15 | | x/4-3=10 | | 16=r-5r | | 71/4x-x=93/8 | | 4x^2/4x^3+12x | | 3c-5=2c+tc | | 3w-(7w+12)=2(w-3) | | 2x+7x=8x | | 1/2x+6=x+1 | | 9(x+1)=9(1+7x)+x | | -9x-7=35 | | -9-7=35 | | 6c+6=36 | | 8-3(k+2)=2-3k | | 4/9n+9=13 | | 16x+x^3=0 | | 0.5x-6=74 | | 6x+8=5x+4 | | c+18=110 | | 1/3x-4=5/6 | | 4/5/11/5 | | r/5=90 |

Equations solver categories