x+2x^2=84

Simple and best practice solution for x+2x^2=84 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+2x^2=84 equation:


Simplifying
x + 2x2 = 84

Solving
x + 2x2 = 84

Solving for variable 'x'.

Reorder the terms:
-84 + x + 2x2 = 84 + -84

Combine like terms: 84 + -84 = 0
-84 + x + 2x2 = 0

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

Divide each side by '2'.
-42 + 0.5x + x2 = 0

Move the constant term to the right:

Add '42' to each side of the equation.
-42 + 0.5x + 42 + x2 = 0 + 42

Reorder the terms:
-42 + 42 + 0.5x + x2 = 0 + 42

Combine like terms: -42 + 42 = 0
0 + 0.5x + x2 = 0 + 42
0.5x + x2 = 0 + 42

Combine like terms: 0 + 42 = 42
0.5x + x2 = 42

The x term is x.  Take half its coefficient (0.5).
Square it (0.25) and add it to both sides.

Add '0.25' to each side of the equation.
0.5x + 0.25 + x2 = 42 + 0.25

Reorder the terms:
0.25 + 0.5x + x2 = 42 + 0.25

Combine like terms: 42 + 0.25 = 42.25
0.25 + 0.5x + x2 = 42.25

Factor a perfect square on the left side:
(x + 0.5)(x + 0.5) = 42.25

Calculate the square root of the right side: 6.5

Break this problem into two subproblems by setting 
(x + 0.5) equal to 6.5 and -6.5.

Subproblem 1

x + 0.5 = 6.5 Simplifying x + 0.5 = 6.5 Reorder the terms: 0.5 + x = 6.5 Solving 0.5 + x = 6.5 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-0.5' to each side of the equation. 0.5 + -0.5 + x = 6.5 + -0.5 Combine like terms: 0.5 + -0.5 = 0.0 0.0 + x = 6.5 + -0.5 x = 6.5 + -0.5 Combine like terms: 6.5 + -0.5 = 6 x = 6 Simplifying x = 6

Subproblem 2

x + 0.5 = -6.5 Simplifying x + 0.5 = -6.5 Reorder the terms: 0.5 + x = -6.5 Solving 0.5 + x = -6.5 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-0.5' to each side of the equation. 0.5 + -0.5 + x = -6.5 + -0.5 Combine like terms: 0.5 + -0.5 = 0.0 0.0 + x = -6.5 + -0.5 x = -6.5 + -0.5 Combine like terms: -6.5 + -0.5 = -7 x = -7 Simplifying x = -7

Solution

The solution to the problem is based on the solutions from the subproblems. x = {6, -7}

See similar equations:

| (-3/-4)^3 | | 4(5x-2)=6(2x+7) | | 2(6u-5)=3(5u+8) | | v-5=3(15-8v) | | 4u=10 | | 8=(x^2)-1 | | 2x^2+8xy+8y^2-13=0 | | 2(9-5x)*-5=y | | 2(3y-4)=5(3-2y) | | 5+9+0.8x=40 | | -60-7n=5+6n | | -9-2v=8v+75 | | 8(5n-3)=2-n | | 8=(x^2)-2x-15 | | 4z+6=9sz-40 | | 2w+8=7w+18 | | -3x(x-4)+4x=3-7 | | 4y+12=9y-20 | | 9x+10=3x+49 | | 31-2v=3v+6 | | 2z+5=3z-1 | | 36=(x^2)+5x | | 5(y-8)=13y | | X/112=7/x | | 12x-4-(8x+3)+(7x+2)=68 | | 3-2(x-2)=5(2x-3)-2(3x-1) | | 3-2(x-2)=5(2x-3)-2(3x-3) | | 5=(4x^2)-x | | 4(3-p)=2 | | ((t^2+50)*180t)-(90t*t^2)=y | | z=8+4i | | Ln(4x)=ln(x+1)+4 |

Equations solver categories