9x^2-21x+28=0

Simple and best practice solution for 9x^2-21x+28=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 9x^2-21x+28=0 equation:


Simplifying
9x2 + -21x + 28 = 0

Reorder the terms:
28 + -21x + 9x2 = 0

Solving
28 + -21x + 9x2 = 0

Solving for variable 'x'.

Begin completing the square.  Divide all terms by
9 the coefficient of the squared term: 

Divide each side by '9'.
3.111111111 + -2.333333333x + x2 = 0

Move the constant term to the right:

Add '-3.111111111' to each side of the equation.
3.111111111 + -2.333333333x + -3.111111111 + x2 = 0 + -3.111111111

Reorder the terms:
3.111111111 + -3.111111111 + -2.333333333x + x2 = 0 + -3.111111111

Combine like terms: 3.111111111 + -3.111111111 = 0.000000000
0.000000000 + -2.333333333x + x2 = 0 + -3.111111111
-2.333333333x + x2 = 0 + -3.111111111

Combine like terms: 0 + -3.111111111 = -3.111111111
-2.333333333x + x2 = -3.111111111

The x term is -2.333333333x.  Take half its coefficient (-1.166666667).
Square it (1.361111112) and add it to both sides.

Add '1.361111112' to each side of the equation.
-2.333333333x + 1.361111112 + x2 = -3.111111111 + 1.361111112

Reorder the terms:
1.361111112 + -2.333333333x + x2 = -3.111111111 + 1.361111112

Combine like terms: -3.111111111 + 1.361111112 = -1.749999999
1.361111112 + -2.333333333x + x2 = -1.749999999

Factor a perfect square on the left side:
(x + -1.166666667)(x + -1.166666667) = -1.749999999

Can't calculate square root of the right side.

The solution to this equation could not be determined.

See similar equations:

| 2-2x=-20 | | -5x-8y=-4 | | (AX+B)C=D | | 8x+(15-5x)-x=39 | | 3x+7y+2z=5 | | f(x)=3(-x)+4 | | (3x/5y)(y^2/6x) | | 10x-10=5x | | 13-b/6=2-0.5b/b | | 30=-180+30x | | 7x^2+2x=37-32x | | f(x)=3(x+9)+4 | | 84=.9 | | 26=2x-8 | | X-84=0.1 | | X-84=93 | | X-(0.1)=84 | | 6.4u=4 | | 0.1-X=84 | | w-7.7=5.63 | | 3(4y+7a)-5(y-12a)= | | X-0.1=84 | | 5(c-4)c=9 | | 3-9(x+7)=9(x-9) | | 3x+54=0 | | 3w-3(w-6)=8(w-2) | | X+40+x=360 | | 4(x^2+x+3)=36 | | 9x+10=3x-2 | | 5x/9=5/6 | | 4x+5(x-5)=5(x-8) | | s^3-5s^2+2s-10=0 |

Equations solver categories