-21=13x-5x^2

Simple and best practice solution for -21=13x-5x^2 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 -21=13x-5x^2 equation:


Simplifying
-21 = 13x + -5x2

Solving
-21 = 13x + -5x2

Solving for variable 'x'.

Reorder the terms:
-21 + -13x + 5x2 = 13x + -13x + -5x2 + 5x2

Combine like terms: 13x + -13x = 0
-21 + -13x + 5x2 = 0 + -5x2 + 5x2
-21 + -13x + 5x2 = -5x2 + 5x2

Combine like terms: -5x2 + 5x2 = 0
-21 + -13x + 5x2 = 0

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

Divide each side by '5'.
-4.2 + -2.6x + x2 = 0

Move the constant term to the right:

Add '4.2' to each side of the equation.
-4.2 + -2.6x + 4.2 + x2 = 0 + 4.2

Reorder the terms:
-4.2 + 4.2 + -2.6x + x2 = 0 + 4.2

Combine like terms: -4.2 + 4.2 = 0.0
0.0 + -2.6x + x2 = 0 + 4.2
-2.6x + x2 = 0 + 4.2

Combine like terms: 0 + 4.2 = 4.2
-2.6x + x2 = 4.2

The x term is -2.6x.  Take half its coefficient (-1.3).
Square it (1.69) and add it to both sides.

Add '1.69' to each side of the equation.
-2.6x + 1.69 + x2 = 4.2 + 1.69

Reorder the terms:
1.69 + -2.6x + x2 = 4.2 + 1.69

Combine like terms: 4.2 + 1.69 = 5.89
1.69 + -2.6x + x2 = 5.89

Factor a perfect square on the left side:
(x + -1.3)(x + -1.3) = 5.89

Calculate the square root of the right side: 2.42693222

Break this problem into two subproblems by setting 
(x + -1.3) equal to 2.42693222 and -2.42693222.

Subproblem 1

x + -1.3 = 2.42693222 Simplifying x + -1.3 = 2.42693222 Reorder the terms: -1.3 + x = 2.42693222 Solving -1.3 + x = 2.42693222 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.3' to each side of the equation. -1.3 + 1.3 + x = 2.42693222 + 1.3 Combine like terms: -1.3 + 1.3 = 0.0 0.0 + x = 2.42693222 + 1.3 x = 2.42693222 + 1.3 Combine like terms: 2.42693222 + 1.3 = 3.72693222 x = 3.72693222 Simplifying x = 3.72693222

Subproblem 2

x + -1.3 = -2.42693222 Simplifying x + -1.3 = -2.42693222 Reorder the terms: -1.3 + x = -2.42693222 Solving -1.3 + x = -2.42693222 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.3' to each side of the equation. -1.3 + 1.3 + x = -2.42693222 + 1.3 Combine like terms: -1.3 + 1.3 = 0.0 0.0 + x = -2.42693222 + 1.3 x = -2.42693222 + 1.3 Combine like terms: -2.42693222 + 1.3 = -1.12693222 x = -1.12693222 Simplifying x = -1.12693222

Solution

The solution to the problem is based on the solutions from the subproblems. x = {3.72693222, -1.12693222}

See similar equations:

| -5x+8+6x=11 | | 8-(6x+3)+4x=-5 | | 21b^3+51b^2+18b=0 | | 17=15x-3 | | x+3(0)=-3 | | 4-(2)(b-14)=5 | | 2x^2=11x+63 | | 5(n-1)=2(n+3) | | 7x^2+20=252 | | x^2+y^2=220.5 | | (2x+25)(2x+10)-250=304 | | 28a^3-256a^2-240a=0 | | -10=0.25(8y-12) | | -13=-x-7 | | 4x^2+70x=304 | | -2w(w-7)+8w+3= | | 32y=3(y+2) | | x-22=2(x+5) | | -2x^2+12x+32=0 | | -10=2x+x-10 | | x+0=-5 | | 10x-15+14x+4=37 | | -2x^2+12x+32x=0 | | n-6=-6 | | (3x+7)(2x^2-17x+30)=0 | | 2x^2+12x+32x=0 | | 2(x-1)-6=10(x-1)+6 | | 4x+5-3x=12 | | 16-x=2x+3 | | 20x+18=32x | | 4[z+3(z-1)]=3 | | (3m+5)(6m+2)= |

Equations solver categories