Using the equation given, 2x-1, you can plug in x, which is given in the table, and solve.
13 is given for x so you plug 13 into 2x-1;
2(13)-1
26-1
25
you can then check your answer to make sure you did it correctly by plugging in another x number (such as 4) and checking to see if you get the same number as the one given.
