The surface area of an oil spill gets 115% larger every day, represented by the function s(x) = (1.15)x − 1. on the first day, it covered an area of 43 square meters. which function would be used to find the area of the oil spill on the 23rd day?

This is the concept of algebra; We are required to find the function that will represent the given information;
Given that the function representing the surface area is s(x)=(1.15)x-1
the initial area of oil is 43 m^2.
since we have to put the initial area into our function, our new expression will be:
s(x)=43(1.15)x-1

the answer is s(x)=43(1.15)x-1