After reading and analyzing a word problem, what is the name of the letter that represents an unknown?

The parabola x = y² - 9 opens: a.)up b.)down c.) right d.)left

What is the value of x in the following equation? -3x-2=2x+8

The graph shows the charges for a health club in a month. make a function table for the input-output values. writes an equation that can be used to find the total charge y for the number of x classes