1. ## differential equation

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From the example above, they tried to solve that differential equation, I didn't understand why in #2 step they have -x ?

I mean this (dy)/(y-6) = -x(dx)

How did they get that -x(dx)?

2. Originally Posted by Pupka
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From the example above, they tried to solve that differential equation, I didn't understand why in #2 step they have -x ?

I mean this (dy)/(y-6) = -x(dx)

How did they get that -x(dx)?
This is using seperation of variables (with a slight abuse of notation) we have:

dy/dx = x (6-y),

so:

dy/(6-y) = x dx

Now we could work with this but it is a bit more convienient to have the
coefficient of y in the denominator on the left to be +1, so we multiply
through by -1 to get:

dy/(y-6) = -x dx

RonL

3. Thanks so much!!!!