-x^2-7x+20=0

Simple and best practice solution for -x^2-7x+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^2-7x+20=0 equation:


Simplifying
-1x2 + -7x + 20 = 0

Reorder the terms:
20 + -7x + -1x2 = 0

Solving
20 + -7x + -1x2 = 0

Solving for variable 'x'.

Begin completing the square.  Divide all terms by
-1 the coefficient of the squared term: 

Divide each side by '-1'.
-20 + 7x + x2 = 0

Move the constant term to the right:

Add '20' to each side of the equation.
-20 + 7x + 20 + x2 = 0 + 20

Reorder the terms:
-20 + 20 + 7x + x2 = 0 + 20

Combine like terms: -20 + 20 = 0
0 + 7x + x2 = 0 + 20
7x + x2 = 0 + 20

Combine like terms: 0 + 20 = 20
7x + x2 = 20

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 = 20 + 12.25

Reorder the terms:
12.25 + 7x + x2 = 20 + 12.25

Combine like terms: 20 + 12.25 = 32.25
12.25 + 7x + x2 = 32.25

Factor a perfect square on the left side:
(x + 3.5)(x + 3.5) = 32.25

Calculate the square root of the right side: 5.678908346

Break this problem into two subproblems by setting 
(x + 3.5) equal to 5.678908346 and -5.678908346.

Subproblem 1

x + 3.5 = 5.678908346 Simplifying x + 3.5 = 5.678908346 Reorder the terms: 3.5 + x = 5.678908346 Solving 3.5 + x = 5.678908346 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 = 5.678908346 + -3.5 Combine like terms: 3.5 + -3.5 = 0.0 0.0 + x = 5.678908346 + -3.5 x = 5.678908346 + -3.5 Combine like terms: 5.678908346 + -3.5 = 2.178908346 x = 2.178908346 Simplifying x = 2.178908346

Subproblem 2

x + 3.5 = -5.678908346 Simplifying x + 3.5 = -5.678908346 Reorder the terms: 3.5 + x = -5.678908346 Solving 3.5 + x = -5.678908346 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 = -5.678908346 + -3.5 Combine like terms: 3.5 + -3.5 = 0.0 0.0 + x = -5.678908346 + -3.5 x = -5.678908346 + -3.5 Combine like terms: -5.678908346 + -3.5 = -9.178908346 x = -9.178908346 Simplifying x = -9.178908346

Solution

The solution to the problem is based on the solutions from the subproblems. x = {2.178908346, -9.178908346}

See similar equations:

| 3(x+4)+6=8x-5(x-6) | | 8y+22=5(y+8) | | a^3-36a=0 | | 4v+3(v+2)=27 | | x/7-2=-5 | | 15(y+3)=3(3y+5) | | 11=5(u-5)+7u | | 2x-6x+25=3x+32 | | 6/3x-x^2/3x | | (1/2+1/3)^2 | | 2x^2=117 | | (3/z)-(1/5z)=5/6 | | 6-8x+7+4x+5x-2=9+2*3 | | 2x^2+kx+1=0 | | 5x+5-7x=15-12+10x-10 | | 3975=10x^2+225x+3100 | | 24-(85/8) | | 18+2d=39-5d | | 43=9x/2+1/2+x/3-3/3 | | (6*3)+72/8-5+1 | | 3590=10x^2+265x+3100 | | ax+b=a-bx | | 10+8q=14+7q | | 4205=10x^2+285x+2700 | | 3x+(6/7)=0 | | 4205=10x^2+285+2700 | | 300=46.71+(51.39x) | | 300=.22+(.016x) | | 8x-4w+4y+2w+3x+7y= | | 22/5x21/2 | | 1/6x-1/3y=-10 | | (5/x)-4=(2/3) |

Equations solver categories