x^2+21-4x=0

Simple and best practice solution for x^2+21-4x=0 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^2+21-4x=0 equation:


Simplifying
x2 + 21 + -4x = 0

Reorder the terms:
21 + -4x + x2 = 0

Solving
21 + -4x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '-21' to each side of the equation.
21 + -4x + -21 + x2 = 0 + -21

Reorder the terms:
21 + -21 + -4x + x2 = 0 + -21

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

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

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 = -21 + 4

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

Combine like terms: -21 + 4 = -17
4 + -4x + x2 = -17

Factor a perfect square on the left side:
(x + -2)(x + -2) = -17

Can't calculate square root of the right side.

The solution to this equation could not be determined.

See similar equations:

| 7+6(1-7v)=v+13 | | 40x=8x^2+50 | | -2v-v+12=-3v^2+6v | | 56x+x^2-x^3=0 | | 5(3n-24)=8*2n | | 32y+4y^2-y^3=0 | | 32+4y-y^2=0 | | (3x+5)3=14x | | 13x^2-9x=0 | | 3y=312 | | 56+x-x^2=0 | | -2(a+3)-a=19 | | y^2+8y+7=0 | | 15x^2+14x-49=0 | | 12x-48=87+7x | | x+x^2-90=0 | | 12+6n=6+8(-8n-8) | | 2=3-x | | 3(d+12)=(d+3)*4 | | 3=7-x | | 5x+x^2-14=0 | | (5t-3)2=(t+3)*-2 | | y^2-14y+45=0 | | -x-4x=10 | | X^2=-12x | | -1=4x-5x | | x+(x*4)=40 | | y=-4x^2-12x-8 | | 11x-49=95-x | | 2(5.2y)+2(y-1)=P | | -2x-3x=15 | | 2(7z-1)-6(z+3)=5(2+1) |

Equations solver categories