x(x-4)=21

Simple and best practice solution for x(x-4)=21 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-4)=21 equation:


Simplifying
x(x + -4) = 21

Reorder the terms:
x(-4 + x) = 21
(-4 * x + x * x) = 21
(-4x + x2) = 21

Solving
-4x + x2 = 21

Solving for variable 'x'.

Reorder the terms:
-21 + -4x + x2 = 21 + -21

Combine like terms: 21 + -21 = 0
-21 + -4x + x2 = 0

Factor a trinomial.
(-3 + -1x)(7 + -1x) = 0

Subproblem 1

Set the factor '(-3 + -1x)' equal to zero and attempt to solve: Simplifying -3 + -1x = 0 Solving -3 + -1x = 0 Move all terms containing x to the left, all other terms to the right. Add '3' to each side of the equation. -3 + 3 + -1x = 0 + 3 Combine like terms: -3 + 3 = 0 0 + -1x = 0 + 3 -1x = 0 + 3 Combine like terms: 0 + 3 = 3 -1x = 3 Divide each side by '-1'. x = -3 Simplifying x = -3

Subproblem 2

Set the factor '(7 + -1x)' equal to zero and attempt to solve: Simplifying 7 + -1x = 0 Solving 7 + -1x = 0 Move all terms containing x to the left, all other terms to the right. Add '-7' to each side of the equation. 7 + -7 + -1x = 0 + -7 Combine like terms: 7 + -7 = 0 0 + -1x = 0 + -7 -1x = 0 + -7 Combine like terms: 0 + -7 = -7 -1x = -7 Divide each side by '-1'. x = 7 Simplifying x = 7

Solution

x = {-3, 7}

See similar equations:

| X=12(-3*6) | | 8z-3=6z | | 7x-4=2x-9 | | -3+r=5 | | 9m-4=2-3m | | -5=x+1 | | 8n-3=4n+9 | | -z=55 | | 40=-8x | | 7m-4=2-m | | -6x=-48 | | 6x+5x-70=5x+54-70 | | 10=v-7 | | 6k+2=k-3 | | -2(3x-1)=-46 | | -1+x=2 | | 5h-3=2h+4 | | -12-4r=7r+17 | | -3+x+5-3x=-1 | | 6d-3=4-2d | | 14x+2y=0 | | 4x^2+28x-32=0 | | 4b-2=2b+5 | | 4x^2+28-32=0 | | 7a+1=2a-3 | | W^2-8w=0 | | 30+5x-32=7x+12-9x | | 4-2a+8+5a=-9 | | 2b-3=5b+1 | | y=3-2x | | 2x-4+6x=22-15+21 | | 99-9k=9k-9 |

Equations solver categories