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I am having really problems getting my head around the below, making y the subject:

 

x = yz + y.         Answer  y = x/z + 1

 

where does the + 1 come from?  Is the + y the same as + 1?

 

Thanks

 Jan 29, 2018
 #1
avatar+109527 
+1

It is NOT    y=x/z + 1      IT IS      t=x/(z+1)      there is a big difference  angry

 

\(x = yz + y \)

 

the aim is to make y the subject so the first thing you have to do it to facot out the y (so that you will only see one y)

 

\(yz+y =y*z+y*1= y(z+1)\)

 

so

 

\(x = yz + y\\ x=y(z+1) \)

 

Now you want the y bt itself. At the moment it is multipled by (z+1) the opposite of multiply is divide. 

SO you have to divide BOTH sides by (z+1)

 

\(x = yz + y\\ x=y(z+1)\\ \frac{x}{z+1}=\frac{y(z+1)}{z+1}\\ now \;\;cancel\\ \frac{x}{z+1}=y\\ \text{Now swap sides}\\ y=\frac{x}{z+1} \)

.
 Jan 29, 2018

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