Question 186664
I'll do the first two to get you going in the right direction.


# 1




I'm assuming that the equation is {{{y=3^x-4}}}.



The parent function is {{{y=3^x}}} which looks like 



{{{ drawing(500, 500, -10, 10, -10, 10,
 graph( 500, 500, -10, 10, -10, 10,3^x)

)}}} Graph of {{{y=3^x}}}




and the function {{{y=3^x-4}}} is simply the parent function shifted down 4 units like this  



{{{ drawing(500, 500, -10, 10, -10, 10,
 graph( 500, 500, -10, 10, -10, 10,3^x,3^x-4)

)}}} Graph of {{{y=3^x}}} (red) and {{{y=3^x-4}}} (green)




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# 2


{{{log(10,(a))-log(10,(ab))}}} Start with the given expression.



{{{log(10,(a/(ab)))}}} Combine the logs using the identity {{{log(b,(A))-log(b,(B))=log(b,(A/B))}}}



{{{log(10,(cross(a)/(cross(a)*b)))}}} Cancel out the common terms.



{{{log(10,(1/b))}}}



So {{{log(10,(a))-log(10,(ab))=log(10,(1/b))}}} where {{{a>0}}} and {{{b>0}}}