Since there are 3 sculptors and 5 photographers, and the question is asking for either a sculptor or photographer, you add them together. There are a total of 18 artists, and the probability is the chance of a certain thing happening over the total amount of things that can happen (i.e. a coin landing on heads is 50%).
The way to answer this problem given different points and different equations in the choices is to do substitution and trial and error. In this regard, we substitute for example 4 to x in the equations and check which of them yields 89. The answer is D.
so you divide -25 by 5 and the rule is if it is division for exponents then you subtract the exponent so 6-2=4, 7-4=3, 3-3=0. z^0 is 1 so we don't have to write it out.