Find the solutioin to x^2=18

Pls! does anybody know a shortcut for answering these types of questions in the future?

Data are collected to see how many ice-cream cones are sold at a ballpark in a week. day 1 is sunday and day 7 is the following saturday. use the data from the table to create a scatter plot.

Louis wants to carpet the rectangular floor of his basement. the basement has an area of 864 square feet. the width of the basement is 2/3 it's length. what is the length of louis's basement