- #1

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## Homework Statement

(x+2y+3)dx+(2x+4y-1)dy=0

a

_{1}= 1 b

_{1}=2 a

_{2}=2 b

_{2}=4

a

_{2}/a

_{1}=b

_{2}/b

_{1}

Therefore z=x+2y

Here is where I get confused I understand that they must get a dz in the equations thus they take the derivative with respect to y of the following equation z=x+2y

thus giving dz=dx+2 or dz-dx/2

What I dont understand is the simplification process that occurs now

(z+3)dx +(2z-1)(dz-dx/2)=0

then the book goes on to transform it into

7dx + (2z-1)dz=0

I have no idea what they did to get to that step.