(x-4)(x+8)=39

Simple and best practice solution for (x-4)(x+8)=39 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-4)(x+8)=39 equation:


Simplifying
(x + -4)(x + 8) = 39

Reorder the terms:
(-4 + x)(x + 8) = 39

Reorder the terms:
(-4 + x)(8 + x) = 39

Multiply (-4 + x) * (8 + x)
(-4(8 + x) + x(8 + x)) = 39
((8 * -4 + x * -4) + x(8 + x)) = 39
((-32 + -4x) + x(8 + x)) = 39
(-32 + -4x + (8 * x + x * x)) = 39
(-32 + -4x + (8x + x2)) = 39

Combine like terms: -4x + 8x = 4x
(-32 + 4x + x2) = 39

Solving
-32 + 4x + x2 = 39

Solving for variable 'x'.

Reorder the terms:
-32 + -39 + 4x + x2 = 39 + -39

Combine like terms: -32 + -39 = -71
-71 + 4x + x2 = 39 + -39

Combine like terms: 39 + -39 = 0
-71 + 4x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '71' to each side of the equation.
-71 + 4x + 71 + x2 = 0 + 71

Reorder the terms:
-71 + 71 + 4x + x2 = 0 + 71

Combine like terms: -71 + 71 = 0
0 + 4x + x2 = 0 + 71
4x + x2 = 0 + 71

Combine like terms: 0 + 71 = 71
4x + x2 = 71

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 = 71 + 4

Reorder the terms:
4 + 4x + x2 = 71 + 4

Combine like terms: 71 + 4 = 75
4 + 4x + x2 = 75

Factor a perfect square on the left side:
(x + 2)(x + 2) = 75

Calculate the square root of the right side: 8.660254038

Break this problem into two subproblems by setting 
(x + 2) equal to 8.660254038 and -8.660254038.

Subproblem 1

x + 2 = 8.660254038 Simplifying x + 2 = 8.660254038 Reorder the terms: 2 + x = 8.660254038 Solving 2 + x = 8.660254038 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 = 8.660254038 + -2 Combine like terms: 2 + -2 = 0 0 + x = 8.660254038 + -2 x = 8.660254038 + -2 Combine like terms: 8.660254038 + -2 = 6.660254038 x = 6.660254038 Simplifying x = 6.660254038

Subproblem 2

x + 2 = -8.660254038 Simplifying x + 2 = -8.660254038 Reorder the terms: 2 + x = -8.660254038 Solving 2 + x = -8.660254038 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 = -8.660254038 + -2 Combine like terms: 2 + -2 = 0 0 + x = -8.660254038 + -2 x = -8.660254038 + -2 Combine like terms: -8.660254038 + -2 = -10.660254038 x = -10.660254038 Simplifying x = -10.660254038

Solution

The solution to the problem is based on the solutions from the subproblems. x = {6.660254038, -10.660254038}

See similar equations:

| (7x+3)+(x+2)= | | 9v+5=4v+5 | | 7x^4-2x^3= | | 1(x-9)-8=-4x+(-32) | | 2x-18=2(x-9) | | -70-2.25x=-182.5 | | 7(x+6)-30=1x+18 | | -70-2.25(60)= | | -5(8+x)=-38-8x | | 75=100-D | | -70-2.25(100)= | | 15(x-5)+57=-x-2 | | (15-c)+3=13 | | 100=75-D | | 9+10x=3x+14 | | X-4=yu | | 9+3x=5+8x | | -50+2x(0)=0 | | -7(7x-7)+4=-49x+53 | | -0.6x+0.42=0.5 | | 13r+18=12r-18 | | 18-12r=13r+18 | | 90+20(-4)= | | 90+20(-2)= | | 5h-7=2(1h+1) | | 3x+3x=1000 | | 15a^2-20a=0 | | -0.3+2z=-0.83 | | 264=10x+x^2 | | x-.21x=2 | | 11p+q-13p+15q= | | 0.12(x+30)=42 |

Equations solver categories