x=20-(21x/100)

Solution for x=20-(21x/100) equation:

x=20-(21x/100)

We move all terms to the left:

x-(20-(21x/100))=0

We add all the numbers together, and all the variables

x-(20-(+21x/100))=0

We multiply all the terms by the denominator


x*100))-(20-(+21x=0

We add all the numbers together, and all the variables

21x+x*100))-(20-(=0

Wy multiply elements

100x^2+21x=0

a = 100; b = 21; c = 0;
Δ = b2-4ac
Δ = 212-4·100·0
Δ = 441
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{441}=21$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-21}{2*100}=\frac{-42}{200}
=-21/100
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+21}{2*100}=\frac{0}{200}
=0
$