Can someone plz explain how to solve a problem like this Exponent 3 sq root 10

Imagine a new pasture with grass growing on it. every day after the seeds have germinated, the number of blades of grass in the pasture triples. after 18 days, the entire pasture is completely covered in grass. how many days did it take for the pasture to be one-third covered in grass?

What is the length of the segment joining the points at (4,5) and (6,-2) round to the nearest tenth if necessary

Which conjunction is disjunction is equivalent to the given absolute value inequality? |x+2|< 18