2d^2-10d-9=0

Simple and best practice solution for 2d^2-10d-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 2d^2-10d-9=0 equation:


Simplifying
2d2 + -10d + -9 = 0

Reorder the terms:
-9 + -10d + 2d2 = 0

Solving
-9 + -10d + 2d2 = 0

Solving for variable 'd'.

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

Divide each side by '2'.
-4.5 + -5d + d2 = 0

Move the constant term to the right:

Add '4.5' to each side of the equation.
-4.5 + -5d + 4.5 + d2 = 0 + 4.5

Reorder the terms:
-4.5 + 4.5 + -5d + d2 = 0 + 4.5

Combine like terms: -4.5 + 4.5 = 0.0
0.0 + -5d + d2 = 0 + 4.5
-5d + d2 = 0 + 4.5

Combine like terms: 0 + 4.5 = 4.5
-5d + d2 = 4.5

The d term is -5d.  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.
-5d + 6.25 + d2 = 4.5 + 6.25

Reorder the terms:
6.25 + -5d + d2 = 4.5 + 6.25

Combine like terms: 4.5 + 6.25 = 10.75
6.25 + -5d + d2 = 10.75

Factor a perfect square on the left side:
(d + -2.5)(d + -2.5) = 10.75

Calculate the square root of the right side: 3.278719262

Break this problem into two subproblems by setting 
(d + -2.5) equal to 3.278719262 and -3.278719262.

Subproblem 1

d + -2.5 = 3.278719262 Simplifying d + -2.5 = 3.278719262 Reorder the terms: -2.5 + d = 3.278719262 Solving -2.5 + d = 3.278719262 Solving for variable 'd'. Move all terms containing d to the left, all other terms to the right. Add '2.5' to each side of the equation. -2.5 + 2.5 + d = 3.278719262 + 2.5 Combine like terms: -2.5 + 2.5 = 0.0 0.0 + d = 3.278719262 + 2.5 d = 3.278719262 + 2.5 Combine like terms: 3.278719262 + 2.5 = 5.778719262 d = 5.778719262 Simplifying d = 5.778719262

Subproblem 2

d + -2.5 = -3.278719262 Simplifying d + -2.5 = -3.278719262 Reorder the terms: -2.5 + d = -3.278719262 Solving -2.5 + d = -3.278719262 Solving for variable 'd'. Move all terms containing d to the left, all other terms to the right. Add '2.5' to each side of the equation. -2.5 + 2.5 + d = -3.278719262 + 2.5 Combine like terms: -2.5 + 2.5 = 0.0 0.0 + d = -3.278719262 + 2.5 d = -3.278719262 + 2.5 Combine like terms: -3.278719262 + 2.5 = -0.778719262 d = -0.778719262 Simplifying d = -0.778719262

Solution

The solution to the problem is based on the solutions from the subproblems. d = {5.778719262, -0.778719262}

See similar equations:

| x+0.14x=18.24 | | x+(x+16)=90 | | x-0.25x=24 | | 4.08(x-14)-2.80x=47.84 | | 4x^2+16x+3=0 | | -2m+7=m+3 | | 0=3(x+5)-9 | | 8-4t=2 | | -3(m+44)=8m | | 12x+3=-6 | | -2n-7-5n=-49 | | x+85=3x-43 | | -4+7+2n=1 | | a^2-14a+49=0 | | 3n^2-7n-8=0 | | 32x=500 | | x^4+2*x^2-5=0 | | 32x=100 | | -x^4+2*x^2-2=0 | | -x^4+2*x^2-4=0 | | 5-2(-2)=7 | | 8x^2+20x=57 | | 4x-9=-4 | | -x^4+2*x^2-5=0 | | x+0.15x=19.55 | | 4x+7=2x+39 | | 11-9x=56-44x | | 24+4x=168-4x | | 5x+158=13x-10 | | 4x-102=x | | 102-4x=x | | 3x+13=103-3x |

Equations solver categories