-3x^2+21x=15

Simple and best practice solution for -3x^2+21x=15 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 -3x^2+21x=15 equation:


Simplifying
-3x2 + 21x = 15

Reorder the terms:
21x + -3x2 = 15

Solving
21x + -3x2 = 15

Solving for variable 'x'.

Reorder the terms:
-15 + 21x + -3x2 = 15 + -15

Combine like terms: 15 + -15 = 0
-15 + 21x + -3x2 = 0

Factor out the Greatest Common Factor (GCF), '3'.
3(-5 + 7x + -1x2) = 0

Ignore the factor 3.

Subproblem 1

Set the factor '(-5 + 7x + -1x2)' equal to zero and attempt to solve: Simplifying -5 + 7x + -1x2 = 0 Solving -5 + 7x + -1x2 = 0 Begin completing the square. Divide all terms by -1 the coefficient of the squared term: Divide each side by '-1'. 5 + -7x + x2 = 0 Move the constant term to the right: Add '-5' to each side of the equation. 5 + -7x + -5 + x2 = 0 + -5 Reorder the terms: 5 + -5 + -7x + x2 = 0 + -5 Combine like terms: 5 + -5 = 0 0 + -7x + x2 = 0 + -5 -7x + x2 = 0 + -5 Combine like terms: 0 + -5 = -5 -7x + x2 = -5 The x term is -7x. Take half its coefficient (-3.5). Square it (12.25) and add it to both sides. Add '12.25' to each side of the equation. -7x + 12.25 + x2 = -5 + 12.25 Reorder the terms: 12.25 + -7x + x2 = -5 + 12.25 Combine like terms: -5 + 12.25 = 7.25 12.25 + -7x + x2 = 7.25 Factor a perfect square on the left side: (x + -3.5)(x + -3.5) = 7.25 Calculate the square root of the right side: 2.692582404 Break this problem into two subproblems by setting (x + -3.5) equal to 2.692582404 and -2.692582404.

Subproblem 1

x + -3.5 = 2.692582404 Simplifying x + -3.5 = 2.692582404 Reorder the terms: -3.5 + x = 2.692582404 Solving -3.5 + x = 2.692582404 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '3.5' to each side of the equation. -3.5 + 3.5 + x = 2.692582404 + 3.5 Combine like terms: -3.5 + 3.5 = 0.0 0.0 + x = 2.692582404 + 3.5 x = 2.692582404 + 3.5 Combine like terms: 2.692582404 + 3.5 = 6.192582404 x = 6.192582404 Simplifying x = 6.192582404

Subproblem 2

x + -3.5 = -2.692582404 Simplifying x + -3.5 = -2.692582404 Reorder the terms: -3.5 + x = -2.692582404 Solving -3.5 + x = -2.692582404 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '3.5' to each side of the equation. -3.5 + 3.5 + x = -2.692582404 + 3.5 Combine like terms: -3.5 + 3.5 = 0.0 0.0 + x = -2.692582404 + 3.5 x = -2.692582404 + 3.5 Combine like terms: -2.692582404 + 3.5 = 0.807417596 x = 0.807417596 Simplifying x = 0.807417596

Solution

The solution to the problem is based on the solutions from the subproblems. x = {6.192582404, 0.807417596}

Solution

x = {6.192582404, 0.807417596}

See similar equations:

| 5x+5+4x+5+35=180 | | 1=-.5(3k-4) | | 3.50x=84 | | (3+3.50)x=84 | | 5m^2+2=47 | | -2/3q+2q=6/5q+12/5 | | 2[(12+2x)+(15+2x)]=74 | | 8y^2-23y-3= | | (-762.46)=h-32.061 | | 4x-12=72 | | x^2-12x-14=41 | | 21.21+p=(-101.6) | | (3u+7)(8+u)=0 | | cos(3x)=cos(x) | | 17x^2-153=0 | | 11/20+5/20 | | 102.8=g(-66.09) | | b-17.8=(-36) | | x^2-5x=12-4x | | 7/8x-1/4+3/8x=1/16x | | 9/35+6/35 | | (-332)=(-129)+s | | 7/2x+1/2x=3x3/2+5/2x | | x^2+81/x^2=18 | | 4x=24x^2 | | w-454=(-832) | | x^4-18x^2-81=0 | | 2x^2+-9x+9=0 | | 4x=-24x^2 | | 2y^2-24y=94 | | 10=-3m-14 | | 17.7x+5.3y=552 |

Equations solver categories