x^2+42x+20=0

Simple and best practice solution for x^2+42x+20=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 x^2+42x+20=0 equation:


Simplifying
x2 + 42x + 20 = 0

Reorder the terms:
20 + 42x + x2 = 0

Solving
20 + 42x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '-20' to each side of the equation.
20 + 42x + -20 + x2 = 0 + -20

Reorder the terms:
20 + -20 + 42x + x2 = 0 + -20

Combine like terms: 20 + -20 = 0
0 + 42x + x2 = 0 + -20
42x + x2 = 0 + -20

Combine like terms: 0 + -20 = -20
42x + x2 = -20

The x term is 42x.  Take half its coefficient (21).
Square it (441) and add it to both sides.

Add '441' to each side of the equation.
42x + 441 + x2 = -20 + 441

Reorder the terms:
441 + 42x + x2 = -20 + 441

Combine like terms: -20 + 441 = 421
441 + 42x + x2 = 421

Factor a perfect square on the left side:
(x + 21)(x + 21) = 421

Calculate the square root of the right side: 20.518284529

Break this problem into two subproblems by setting 
(x + 21) equal to 20.518284529 and -20.518284529.

Subproblem 1

x + 21 = 20.518284529 Simplifying x + 21 = 20.518284529 Reorder the terms: 21 + x = 20.518284529 Solving 21 + x = 20.518284529 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-21' to each side of the equation. 21 + -21 + x = 20.518284529 + -21 Combine like terms: 21 + -21 = 0 0 + x = 20.518284529 + -21 x = 20.518284529 + -21 Combine like terms: 20.518284529 + -21 = -0.481715471 x = -0.481715471 Simplifying x = -0.481715471

Subproblem 2

x + 21 = -20.518284529 Simplifying x + 21 = -20.518284529 Reorder the terms: 21 + x = -20.518284529 Solving 21 + x = -20.518284529 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-21' to each side of the equation. 21 + -21 + x = -20.518284529 + -21 Combine like terms: 21 + -21 = 0 0 + x = -20.518284529 + -21 x = -20.518284529 + -21 Combine like terms: -20.518284529 + -21 = -41.518284529 x = -41.518284529 Simplifying x = -41.518284529

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-0.481715471, -41.518284529}

See similar equations:

| b^2-2b-58=-8 | | (-4x+3)(-4x+3)= | | 3x+29=5 | | 2x=26+16 | | v^2-8v-12=-3 | | k^2-16k+35=7 | | 2x^2+84x+40=0 | | w=5+.5w | | -7/2(y-8)-1/6y= | | x=mb+y | | 10x-231=2x-7 | | 1x+5y=16.24 | | -3(r-7)+4=-15 | | 6x-19=2x+6 | | -6x(-4x-2)=36 | | 40r^2-42+9=0 | | -45x-45=-75+75 | | 12=5cos(2x)+7 | | -3+5x-x=-47 | | f(x)=x^2+5x-4 | | b^2+20b+64=0 | | 27x-1+10y=180 | | 5(175)= | | 3x+42=5x-64 | | 12+.15m=23+.11m | | x^2-19x-71=0 | | p^2-17p-39=0 | | w^3-2w^2-9w+9=6w+9 | | T/5=49 | | 2y+4+3+3x=0 | | .03(y-2)+.04y=.03y-.6 | | (0.3c+0.3)(c+0.7)= |

Equations solver categories