What is the value 8x=5x+21

Elena is paid a constant rate for each hour she works. the table shows the amounts of money that elena earned for various amounts of time that she worked.

These box plots show the number of electoral votes one by democratic and republican presidential candidates for the elections from 1984 through 2012. which statement best compares the spread of the data sets

At noon a tank contained 10cm water. after several hours it contained 7cm of water. what is the percent decrease of water in the tank?