Question

what is the variable in the expression 4x - 9?
a. -9
b. x
c. 4x
d. 4

Explanation:

A variable is a symbol representing an unknown quantity. In \(4x - 9\), \(x\) is the symbol for the unknown value, so it is the variable. The other options are constants (\(-9\), \(4\)) or a term with a coefficient and variable (\(4x\)).

Answer:

b. \(x\)