x=1/2x+20

Solution for x=1/2x+20 equation:

x=1/2x+20

We move all terms to the left:

x-(1/2x+20)=0


Domain of the equation: 2x+20)!=0

x∈R


We get rid of parentheses

x-1/2x-20=0

We multiply all the terms by the denominator


x*2x-20*2x-1=0

Wy multiply elements

2x^2-40x-1=0

a = 2; b = -40; c = -1;
Δ = b2-4ac
Δ = -402-4·2·(-1)
Δ = 1608
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1608}=\sqrt{4*402}=\sqrt{4}*\sqrt{402}=2\sqrt{402}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-2\sqrt{402}}{2*2}=\frac{40-2\sqrt{402}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+2\sqrt{402}}{2*2}=\frac{40+2\sqrt{402}}{4}
$