s+21/2s+20s=55

Solution for s+21/2s+20s=55 equation:

s+21/2s+20s=55

We move all terms to the left:

s+21/2s+20s-(55)=0


Domain of the equation: 2s!=0

s!=0/2

s!=0

s∈R


We add all the numbers together, and all the variables

21s+21/2s-55=0

We multiply all the terms by the denominator


21s*2s-55*2s+21=0

Wy multiply elements

42s^2-110s+21=0

a = 42; b = -110; c = +21;
Δ = b2-4ac
Δ = -1102-4·42·21
Δ = 8572
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{8572}=\sqrt{4*2143}=\sqrt{4}*\sqrt{2143}=2\sqrt{2143}$
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-110)-2\sqrt{2143}}{2*42}=\frac{110-2\sqrt{2143}}{84}
$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-110)+2\sqrt{2143}}{2*42}=\frac{110+2\sqrt{2143}}{84}
$