For what value of x is the rational expression below equal to zero?

The rational expression will be zero when its numerator is zero and its denominator is NOT zero.  

3x + 15 = 0

3x = -15

x = -5

We check and the denominator 6 - x = 6 - -5 = 11, not zero, good.

D.  -5

logv3(x+2)=1

rewrite in exponential form:

logb(x) = y is equal to b^y =x

b = 3, y = 1

now solve for x:

3^1 = x+2)

x = 3-2

x = 1

see the picture for the graph.