Functions and Algebra question. Given the function $g(x) = 8 − 2x$


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*Find $g(2x-3)$ 


The answer to the question is $14-4x$ 
I have no idea how the lecturer worked it out and I just jotted down the answer, while trying to do it I just can't seem to work it out. If anyone could give me the steps to tackle this problem it'd be greatly appreciated. 

Given that $g(x)=8-2x$, let $Y=2x-3$. 
Then, $g(Y)=8-2Y=8-2(2x-3)=8-4x+6=14-4x$. 
