x*x-15=4x

Simple and best practice solution for x*x-15=4x 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*x-15=4x equation:


Simplifying
x * x + -15 = 4x

Multiply x * x
x2 + -15 = 4x

Reorder the terms:
-15 + x2 = 4x

Solving
-15 + x2 = 4x

Solving for variable 'x'.

Reorder the terms:
-15 + -4x + x2 = 4x + -4x

Combine like terms: 4x + -4x = 0
-15 + -4x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '15' to each side of the equation.
-15 + -4x + 15 + x2 = 0 + 15

Reorder the terms:
-15 + 15 + -4x + x2 = 0 + 15

Combine like terms: -15 + 15 = 0
0 + -4x + x2 = 0 + 15
-4x + x2 = 0 + 15

Combine like terms: 0 + 15 = 15
-4x + x2 = 15

The x term is -4x.  Take half its coefficient (-2).
Square it (4) and add it to both sides.

Add '4' to each side of the equation.
-4x + 4 + x2 = 15 + 4

Reorder the terms:
4 + -4x + x2 = 15 + 4

Combine like terms: 15 + 4 = 19
4 + -4x + x2 = 19

Factor a perfect square on the left side:
(x + -2)(x + -2) = 19

Calculate the square root of the right side: 4.358898944

Break this problem into two subproblems by setting 
(x + -2) equal to 4.358898944 and -4.358898944.

Subproblem 1

x + -2 = 4.358898944 Simplifying x + -2 = 4.358898944 Reorder the terms: -2 + x = 4.358898944 Solving -2 + x = 4.358898944 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '2' to each side of the equation. -2 + 2 + x = 4.358898944 + 2 Combine like terms: -2 + 2 = 0 0 + x = 4.358898944 + 2 x = 4.358898944 + 2 Combine like terms: 4.358898944 + 2 = 6.358898944 x = 6.358898944 Simplifying x = 6.358898944

Subproblem 2

x + -2 = -4.358898944 Simplifying x + -2 = -4.358898944 Reorder the terms: -2 + x = -4.358898944 Solving -2 + x = -4.358898944 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '2' to each side of the equation. -2 + 2 + x = -4.358898944 + 2 Combine like terms: -2 + 2 = 0 0 + x = -4.358898944 + 2 x = -4.358898944 + 2 Combine like terms: -4.358898944 + 2 = -2.358898944 x = -2.358898944 Simplifying x = -2.358898944

Solution

The solution to the problem is based on the solutions from the subproblems. x = {6.358898944, -2.358898944}

See similar equations:

| 13.45+0.13(x+3)=13.95-0.08x | | -2k+19=4n+17 | | 5850/30•13 | | 4p+12=-p-4 | | 4x+20+5x=11 | | 13.45+0.13+(x+3)=13.95-0.08x | | 6(2x+7)=5(4-3x) | | 13.45+0.12+(x+3)=13.95-0.08x | | 5d-5b=7 | | SinX=1000 | | 6(2x+20)=24 | | 7+3b=9b-5(2) | | 5x+4-8+3x=8x-4 | | 14x+40=180 | | 17x-9=4x+8 | | 55.534*X=60 | | 3x^5-12x^3+12x=0 | | 9=(7-12) | | Cscx=2sinx+1 | | y-5=(8/3)(x-3) | | C^2=25/36 | | 2x+12-8x=29-1-8x | | 2x-x+5=18 | | -22+6x=2(7x-3) | | 3(v+6)6v=30 | | 15-6n=1-4n | | -2b+8b=-7+6+1 | | 3(6-f)-4=3f+4 | | 3(v+6)+-6v=30 | | 11-2n=1-8n-4n | | 3(v+6)-6v=30 | | 12+3b=8+b |

Equations solver categories