2x^2-21=x

Simple and best practice solution for 2x^2-21=x 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 2x^2-21=x equation:


Simplifying
2x2 + -21 = x

Reorder the terms:
-21 + 2x2 = x

Solving
-21 + 2x2 = x

Solving for variable 'x'.

Reorder the terms:
-21 + -1x + 2x2 = x + -1x

Combine like terms: x + -1x = 0
-21 + -1x + 2x2 = 0

Factor a trinomial.
(-3 + -1x)(7 + -2x) = 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 + -2x)' equal to zero and attempt to solve: Simplifying 7 + -2x = 0 Solving 7 + -2x = 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 + -2x = 0 + -7 Combine like terms: 7 + -7 = 0 0 + -2x = 0 + -7 -2x = 0 + -7 Combine like terms: 0 + -7 = -7 -2x = -7 Divide each side by '-2'. x = 3.5 Simplifying x = 3.5

Solution

x = {-3, 3.5}

See similar equations:

| 3x+3x+5+(7x+6)=180 | | 52=.5((x+6)*(x+5)) | | x+21+3x=-33-3x-37 | | -1.8x-4=-1.1x+3 | | 18*8.5= | | abs(4y-2)=abs(4y+5) | | f(x)=10-2x/3 | | 5g+1h=5 | | x+x+x+63=180 | | 5h+1h=5 | | x=10-2x/3 | | 1.3=2y+10.1 | | I(x)=-3x^2+3000x | | 4x/9-(3x | | 0.6x=1.2 | | 55.5x^2+x-55=0 | | 3f-4d=15c | | 8y-4-4y-9= | | 5/8-40/64 | | y=-x^3+3x^2+18x+40 | | 6(x-4)^2=120 | | 10y-8-2y-9= | | 7x^2+18=50 | | 0.5/50 | | 1/1/18 | | 1.6w-6=.75w | | 3a+4b=87 | | 4n+3.5=8.3 | | 5/7-3/5=x/25 | | 2ln+x+y=4 | | x^3+4x^2+2x-6=0 | | 2lnx+y=4 |

Equations solver categories