x^2-2x-15=8

Simple and best practice solution for x^2-2x-15=8 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 x^2-2x-15=8 equation:


Simplifying
x2 + -2x + -15 = 8

Reorder the terms:
-15 + -2x + x2 = 8

Solving
-15 + -2x + x2 = 8

Solving for variable 'x'.

Reorder the terms:
-15 + -8 + -2x + x2 = 8 + -8

Combine like terms: -15 + -8 = -23
-23 + -2x + x2 = 8 + -8

Combine like terms: 8 + -8 = 0
-23 + -2x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '23' to each side of the equation.
-23 + -2x + 23 + x2 = 0 + 23

Reorder the terms:
-23 + 23 + -2x + x2 = 0 + 23

Combine like terms: -23 + 23 = 0
0 + -2x + x2 = 0 + 23
-2x + x2 = 0 + 23

Combine like terms: 0 + 23 = 23
-2x + x2 = 23

The x term is -2x.  Take half its coefficient (-1).
Square it (1) and add it to both sides.

Add '1' to each side of the equation.
-2x + 1 + x2 = 23 + 1

Reorder the terms:
1 + -2x + x2 = 23 + 1

Combine like terms: 23 + 1 = 24
1 + -2x + x2 = 24

Factor a perfect square on the left side:
(x + -1)(x + -1) = 24

Calculate the square root of the right side: 4.898979486

Break this problem into two subproblems by setting 
(x + -1) equal to 4.898979486 and -4.898979486.

Subproblem 1

x + -1 = 4.898979486 Simplifying x + -1 = 4.898979486 Reorder the terms: -1 + x = 4.898979486 Solving -1 + x = 4.898979486 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1' to each side of the equation. -1 + 1 + x = 4.898979486 + 1 Combine like terms: -1 + 1 = 0 0 + x = 4.898979486 + 1 x = 4.898979486 + 1 Combine like terms: 4.898979486 + 1 = 5.898979486 x = 5.898979486 Simplifying x = 5.898979486

Subproblem 2

x + -1 = -4.898979486 Simplifying x + -1 = -4.898979486 Reorder the terms: -1 + x = -4.898979486 Solving -1 + x = -4.898979486 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1' to each side of the equation. -1 + 1 + x = -4.898979486 + 1 Combine like terms: -1 + 1 = 0 0 + x = -4.898979486 + 1 x = -4.898979486 + 1 Combine like terms: -4.898979486 + 1 = -3.898979486 x = -3.898979486 Simplifying x = -3.898979486

Solution

The solution to the problem is based on the solutions from the subproblems. x = {5.898979486, -3.898979486}

See similar equations:

| 7x^2+x-26=0 | | 4(1-8r)=19 | | y=30+.75(y-20)+185 | | a+b=2x+2b-b | | 0.6-0.1=0.5x+0.2 | | x^4-20x^3+100x^2-x+18=0 | | 60-10=50x+20 | | 1.82=6.2z | | 1.82=6.2 | | 10x^2+6x-6=0 | | (x+20)*(x+20)=14 | | 60-10=5x+20 | | k=4k+4w | | 2.1y=3 | | 42-3y=4y | | 8k-9k=-30 | | 2w=10-3w | | -5=3x-6(-8-7x) | | 3.3a=16 | | 18-4x(-3)= | | 0=2+5t-4.9t^2 | | 4.9t^2-6t+2=0 | | 8d-27+5d-9= | | -9(8b+5)=35 | | -1=-3h | | (5x)y=5(X+Y) | | 9=1+2g | | 2+2c=4 | | 3ln(3)-3ln(4)+2ln(2)=0 | | 6v+7+8v=15 | | 88-4Q=0 | | 3+3x-x+2x=x+2+x |

Equations solver categories