(21-0.8x)(5-0.2x)=0

Simple and best practice solution for (21-0.8x)(5-0.2x)=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 (21-0.8x)(5-0.2x)=0 equation: 


Simplifying
(21 + -0.8x)(5 + -0.2x) = 0

Multiply (21 + -0.8x) * (5 + -0.2x)
(21(5 + -0.2x) + -0.8x * (5 + -0.2x)) = 0
((5 * 21 + -0.2x * 21) + -0.8x * (5 + -0.2x)) = 0
((105 + -4.2x) + -0.8x * (5 + -0.2x)) = 0
(105 + -4.2x + (5 * -0.8x + -0.2x * -0.8x)) = 0
(105 + -4.2x + (-4x + 0.16x2)) = 0

Combine like terms: -4.2x + -4x = -8.2x
(105 + -8.2x + 0.16x2) = 0

Solving
105 + -8.2x + 0.16x2 = 0

Solving for variable 'x'.

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

Divide each side by '0.16'.
656.25 + -51.25x + x2 = 0

Move the constant term to the right:

Add '-656.25' to each side of the equation.
656.25 + -51.25x + -656.25 + x2 = 0 + -656.25

Reorder the terms:
656.25 + -656.25 + -51.25x + x2 = 0 + -656.25

Combine like terms: 656.25 + -656.25 = 0.00
0.00 + -51.25x + x2 = 0 + -656.25
-51.25x + x2 = 0 + -656.25

Combine like terms: 0 + -656.25 = -656.25
-51.25x + x2 = -656.25

The x term is -51.25x.  Take half its coefficient (-25.625).
Square it (656.640625) and add it to both sides.

Add '656.640625' to each side of the equation.
-51.25x + 656.640625 + x2 = -656.25 + 656.640625

Reorder the terms:
656.640625 + -51.25x + x2 = -656.25 + 656.640625

Combine like terms: -656.25 + 656.640625 = 0.390625
656.640625 + -51.25x + x2 = 0.390625

Factor a perfect square on the left side:
(x + -25.625)(x + -25.625) = 0.390625

Calculate the square root of the right side: 0.625

Break this problem into two subproblems by setting 
(x + -25.625) equal to 0.625 and -0.625.


Subproblem 1
x + -25.625 = 0.625

Simplifying
x + -25.625 = 0.625

Reorder the terms:
-25.625 + x = 0.625

Solving
-25.625 + x = 0.625

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '25.625' to each side of the equation.
-25.625 + 25.625 + x = 0.625 + 25.625

Combine like terms: -25.625 + 25.625 = 0.000
0.000 + x = 0.625 + 25.625
x = 0.625 + 25.625

Combine like terms: 0.625 + 25.625 = 26.25
x = 26.25

Simplifying
x = 26.25


Subproblem 2
x + -25.625 = -0.625

Simplifying
x + -25.625 = -0.625

Reorder the terms:
-25.625 + x = -0.625

Solving
-25.625 + x = -0.625

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '25.625' to each side of the equation.
-25.625 + 25.625 + x = -0.625 + 25.625

Combine like terms: -25.625 + 25.625 = 0.000
0.000 + x = -0.625 + 25.625
x = -0.625 + 25.625

Combine like terms: -0.625 + 25.625 = 25
x = 25

Simplifying
x = 25


Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {26.25, 25}

See similar equations:

| 9x=3*(8x+25) | | -3x+2=23x | | -3x+2=23forx | | F(2)=23.8+46.4 | | 3y+10=-10 | | u/8-12= | | 4.1p=11.48 | | 4x-2y=28 | | u/8+12= | | -15m-35-m=13 | | 4.1=11.48 | | 100t=35 | | 6x+17=16c-93 | | F(0)=11.9(0)+46.4 | | 2*(x+2)+4x=28 | | F(0)=11 | | 14+7*40/8-7 | | -7/2x-1/2=2x-1/3 | | 6x4/2 | | x+9.5=2.7 | | -5w+1=-7(w-3) | | A^3-5a^2-36a=0 | | 6x-9=-3x+18 | | c/6=3.4 | | 3z-16=1z | | 19/9-23/12 | | (x^3+2x^2-21x+18)/(x+6) | | G=4t+100 | | 3x+18+x+2=180 | | 5-4y=10 | | 5a+3a+8=300 | | 8-2(-3x-3)=11x+39 |

Equations solver categories