2d^2-5d-8=0

Simple and best practice solution for 2d^2-5d-8=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^2-5d-8=0 equation:


Simplifying
2d2 + -5d + -8 = 0

Reorder the terms:
-8 + -5d + 2d2 = 0

Solving
-8 + -5d + 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 + -2.5d + d2 = 0

Move the constant term to the right:

Add '4' to each side of the equation.
-4 + -2.5d + 4 + d2 = 0 + 4

Reorder the terms:
-4 + 4 + -2.5d + d2 = 0 + 4

Combine like terms: -4 + 4 = 0
0 + -2.5d + d2 = 0 + 4
-2.5d + d2 = 0 + 4

Combine like terms: 0 + 4 = 4
-2.5d + d2 = 4

The d term is -2.5d.  Take half its coefficient (-1.25).
Square it (1.5625) and add it to both sides.

Add '1.5625' to each side of the equation.
-2.5d + 1.5625 + d2 = 4 + 1.5625

Reorder the terms:
1.5625 + -2.5d + d2 = 4 + 1.5625

Combine like terms: 4 + 1.5625 = 5.5625
1.5625 + -2.5d + d2 = 5.5625

Factor a perfect square on the left side:
(d + -1.25)(d + -1.25) = 5.5625

Calculate the square root of the right side: 2.358495283

Break this problem into two subproblems by setting 
(d + -1.25) equal to 2.358495283 and -2.358495283.

Subproblem 1

d + -1.25 = 2.358495283 Simplifying d + -1.25 = 2.358495283 Reorder the terms: -1.25 + d = 2.358495283 Solving -1.25 + d = 2.358495283 Solving for variable 'd'. Move all terms containing d to the left, all other terms to the right. Add '1.25' to each side of the equation. -1.25 + 1.25 + d = 2.358495283 + 1.25 Combine like terms: -1.25 + 1.25 = 0.00 0.00 + d = 2.358495283 + 1.25 d = 2.358495283 + 1.25 Combine like terms: 2.358495283 + 1.25 = 3.608495283 d = 3.608495283 Simplifying d = 3.608495283

Subproblem 2

d + -1.25 = -2.358495283 Simplifying d + -1.25 = -2.358495283 Reorder the terms: -1.25 + d = -2.358495283 Solving -1.25 + d = -2.358495283 Solving for variable 'd'. Move all terms containing d to the left, all other terms to the right. Add '1.25' to each side of the equation. -1.25 + 1.25 + d = -2.358495283 + 1.25 Combine like terms: -1.25 + 1.25 = 0.00 0.00 + d = -2.358495283 + 1.25 d = -2.358495283 + 1.25 Combine like terms: -2.358495283 + 1.25 = -1.108495283 d = -1.108495283 Simplifying d = -1.108495283

Solution

The solution to the problem is based on the solutions from the subproblems. d = {3.608495283, -1.108495283}

See similar equations:

| x+4+6x=4 | | 4(-2m+2)=25 | | 3(4w-3)=15 | | x-34=16 | | in(x)-31n(x)=2 | | -3(4x-1)-2x=4x-69 | | -3(1-6b)-8=5(1+2b) | | 2(5b+4)=38 | | 2x+3=3x-7+5 | | (9+x)(2x+3)=0 | | x-2+3=6 | | v(7)=8 | | 3(2x+1)+5=x+12 | | N^2-8n-23=9 | | x=(128-(129/3-x/3)/2) | | X^2-18x+80=3 | | 3(2n+3)=29 | | -7(v-2)=5v-22 | | -4(3v+6)=-2(1+8v)+2 | | y=-5(0)+2 | | B=10-3*x+2 | | -14a+6=314 | | 1.5x+7=20.5 | | -3y-7=5(y+5) | | (15^1/5) | | (2x)^(1/5) | | 4(3x-5)=20 | | x=(128-(129-x/3)/2 | | -16=x+-15 | | 7y=x+2 | | -7(y-3)=-9y+39 | | (15^1/5)^5 |

Equations solver categories