x^2=12x-21

Simple and best practice solution for x^2=12x-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^2=12x-21 equation:


Simplifying
x2 = 12x + -21

Reorder the terms:
x2 = -21 + 12x

Solving
x2 = -21 + 12x

Solving for variable 'x'.

Reorder the terms:
21 + -12x + x2 = -21 + 12x + 21 + -12x

Reorder the terms:
21 + -12x + x2 = -21 + 21 + 12x + -12x

Combine like terms: -21 + 21 = 0
21 + -12x + x2 = 0 + 12x + -12x
21 + -12x + x2 = 12x + -12x

Combine like terms: 12x + -12x = 0
21 + -12x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-21' to each side of the equation.
21 + -12x + -21 + x2 = 0 + -21

Reorder the terms:
21 + -21 + -12x + x2 = 0 + -21

Combine like terms: 21 + -21 = 0
0 + -12x + x2 = 0 + -21
-12x + x2 = 0 + -21

Combine like terms: 0 + -21 = -21
-12x + x2 = -21

The x term is -12x.  Take half its coefficient (-6).
Square it (36) and add it to both sides.

Add '36' to each side of the equation.
-12x + 36 + x2 = -21 + 36

Reorder the terms:
36 + -12x + x2 = -21 + 36

Combine like terms: -21 + 36 = 15
36 + -12x + x2 = 15

Factor a perfect square on the left side:
(x + -6)(x + -6) = 15

Calculate the square root of the right side: 3.872983346

Break this problem into two subproblems by setting 
(x + -6) equal to 3.872983346 and -3.872983346.

Subproblem 1

x + -6 = 3.872983346 Simplifying x + -6 = 3.872983346 Reorder the terms: -6 + x = 3.872983346 Solving -6 + x = 3.872983346 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '6' to each side of the equation. -6 + 6 + x = 3.872983346 + 6 Combine like terms: -6 + 6 = 0 0 + x = 3.872983346 + 6 x = 3.872983346 + 6 Combine like terms: 3.872983346 + 6 = 9.872983346 x = 9.872983346 Simplifying x = 9.872983346

Subproblem 2

x + -6 = -3.872983346 Simplifying x + -6 = -3.872983346 Reorder the terms: -6 + x = -3.872983346 Solving -6 + x = -3.872983346 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '6' to each side of the equation. -6 + 6 + x = -3.872983346 + 6 Combine like terms: -6 + 6 = 0 0 + x = -3.872983346 + 6 x = -3.872983346 + 6 Combine like terms: -3.872983346 + 6 = 2.127016654 x = 2.127016654 Simplifying x = 2.127016654

Solution

The solution to the problem is based on the solutions from the subproblems. x = {9.872983346, 2.127016654}

See similar equations:

| x+23+129=260 | | Xalcubo+2=10 | | 6.18*0.3= | | 8ln(x+8)=6ln(x) | | 6X+6y=8772 | | 6p^2+78p+252=0 | | 0=(3-x)((1-x)(-4-x)-4)-2(-2(-4-x)-2)+6(4+(1+x))v | | 0.4(x+300)=0.44x-172 | | (X-2)+10=74 | | 15x-7x+8x-2x+5= | | (X-2)3+10=74 | | 7x+21=8x-4 | | x(-2x)+3x+10=0 | | 9x^3+46x^2+5x=0 | | 0=(3-x)((1-x)(-4-x)-4)-2(-2(-4-x)-3)+6(4+(1+x)) | | 7x+90=13x | | 6x-15y=-15 | | Y+0.4=-2x+5 | | -161-x=-17x+143 | | 0=-x^3+7x-4 | | 4z^2+52z+48=0 | | (4x^-5/7y^-8)^-3 | | 48x^3+4x^2-7=0 | | log^5(3x+7)=2 | | w-7/8=-3/4 | | 2(x+6)=4x+(-2) | | 11x-36=24-14x | | z=2(1[x-8]1) | | 7x-12=8x+10 | | 2ln(4x-3)=16 | | 5(z-2)-(3z-1)=3z-6 | | x+9=18+(-2) |

Equations solver categories