slope calculation -electrical - equation help please

Hi, I am new to this website, and learning a bit of math on my own, Need help on this slope calculation, I am looking to learn where the products are coming from in the equation. here is the question. Electrical differential slope calculation – ( w1 is winding 1 and w2 is winding 2 )

SLP1 (slope 1 = 20% or 0.2) IOP = (Iw1 - Iw2) IRT = (Iw1 + Iw2)/2

Equation solve à IOP=SLP1/100 x IRT

Step 1 -> IOP = 0.2/100 x IRT

Step 2 -> (Iw1 - Iw2) = 0.2 x (Iw1 + Iw2)/2

Step 3 -> 2 x (Iw1 - Iw2) = 0.2 x (Iw1 + Iw2)

Step 4 -> 2 x (Iw1 - Iw2)/0.2 = (Iw1 + Iw2)

Step 4 -> 10 x (Iw1 - Iw2) = (Iw1 + Iw2) -> __question 1__ -> where did the “10” come from?

Step 5 -> 10Iw1 – 10Iw2 = Iw1 +Iw2

Step 6 -> 10Iw1 – Iw1 = Iw2 + 10Iw2

Step 7 -> 9Iw1 = 11Iw2 -> __question 2__ -> I get that 10 -1 = 9 and 10 +1 = 11, but why . is this allowed?

Step 8 -> Iw1 = 11/9Iw2

Step 9 -> Iw1 = 1.222Iw2

Step 10 -> 9Iw1 = 11Iw2

Step 11 -> 9/11Iw1 = w2

Step 12 -> Iw2 = 0.818Iw1

Fin! With 2 questions This is for a relay application in per unit, but I am having trouble understanding the theory behind the process here. any help is apprecitated

Re: slope calculation -electrical - equation help please