n(n-1)=840

Simple and best practice solution for n(n-1)=840 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 n(n-1)=840 equation:


Simplifying
n(n + -1) = 840

Reorder the terms:
n(-1 + n) = 840
(-1 * n + n * n) = 840
(-1n + n2) = 840

Solving
-1n + n2 = 840

Solving for variable 'n'.

Reorder the terms:
-840 + -1n + n2 = 840 + -840

Combine like terms: 840 + -840 = 0
-840 + -1n + n2 = 0

Begin completing the square.

Move the constant term to the right:

Add '840' to each side of the equation.
-840 + -1n + 840 + n2 = 0 + 840

Reorder the terms:
-840 + 840 + -1n + n2 = 0 + 840

Combine like terms: -840 + 840 = 0
0 + -1n + n2 = 0 + 840
-1n + n2 = 0 + 840

Combine like terms: 0 + 840 = 840
-1n + n2 = 840

The n term is -1n.  Take half its coefficient (-0.5).
Square it (0.25) and add it to both sides.

Add '0.25' to each side of the equation.
-1n + 0.25 + n2 = 840 + 0.25

Reorder the terms:
0.25 + -1n + n2 = 840 + 0.25

Combine like terms: 840 + 0.25 = 840.25
0.25 + -1n + n2 = 840.25

Factor a perfect square on the left side:
(n + -0.5)(n + -0.5) = 840.25

Calculate the square root of the right side: 28.987066081

Break this problem into two subproblems by setting 
(n + -0.5) equal to 28.987066081 and -28.987066081.

Subproblem 1

n + -0.5 = 28.987066081 Simplifying n + -0.5 = 28.987066081 Reorder the terms: -0.5 + n = 28.987066081 Solving -0.5 + n = 28.987066081 Solving for variable 'n'. Move all terms containing n to the left, all other terms to the right. Add '0.5' to each side of the equation. -0.5 + 0.5 + n = 28.987066081 + 0.5 Combine like terms: -0.5 + 0.5 = 0.0 0.0 + n = 28.987066081 + 0.5 n = 28.987066081 + 0.5 Combine like terms: 28.987066081 + 0.5 = 29.487066081 n = 29.487066081 Simplifying n = 29.487066081

Subproblem 2

n + -0.5 = -28.987066081 Simplifying n + -0.5 = -28.987066081 Reorder the terms: -0.5 + n = -28.987066081 Solving -0.5 + n = -28.987066081 Solving for variable 'n'. Move all terms containing n to the left, all other terms to the right. Add '0.5' to each side of the equation. -0.5 + 0.5 + n = -28.987066081 + 0.5 Combine like terms: -0.5 + 0.5 = 0.0 0.0 + n = -28.987066081 + 0.5 n = -28.987066081 + 0.5 Combine like terms: -28.987066081 + 0.5 = -28.487066081 n = -28.487066081 Simplifying n = -28.487066081

Solution

The solution to the problem is based on the solutions from the subproblems. n = {29.487066081, -28.487066081}

See similar equations:

| -3(-2x+5)=3 | | f(7b)=3(49b)-1 | | 17+3(x-2)=-7(x-2)+14 | | 20-84= | | 6(10-0.5y)-5y=12 | | 3+8n=43 | | 36=3b | | -3(y+3)=39 | | 8x+10-10=8x-12+12 | | 2-4(n-2)=3n+5 | | 3x+5y=15y | | a+5.5=7.3 | | 0.6x+1.9x=65 | | 48+96= | | 5.8+m=8.2 | | 2cos^2x+9cosx+7=0 | | 5x-10=4x-16+x | | 8n-9=-369 | | 16x+2=36x-2 | | 4x-4+x=6x-4-x | | 4+2a=-16+4a | | 2x-2(-2x+2)=-64 | | 2a=120 | | F(x)=3(4-x)-1 | | 9(x-4)+10=9x-25 | | 9(x-8)+9=9x-63 | | X^2-2x-148=0 | | (8x^2y)/(12xy^2) | | G(-x)=3x^2-4x+2 | | 3x^2+3x=x-4 | | 3p^2+29p+75=0 | | 145=1-12x |

Equations solver categories