How long is the hypotenuse of a right triangle with an 8 cm leg and a 15 cm leg?

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?

Iwant to know what 3g+5h+4g-2h is my teacher is too selfish to tell us

Can someone me do math because i am having a breakdown rn because i don’t get it