Question

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

what is the variable in the equation $5 = 9t + 3$?
a. 5
b. t
c. 3
d. 9

what type of term is $5x^2$ in the expression $x + 5x^2 - 3$?
a. numerical term
b. variable term
c. isolated term
d. constant term

Explanation:

First Question: What is the variable in the expression \( 4x - 9 \)?

A variable is a symbol (usually a letter) that represents an unknown or changing quantity. In \( 4x - 9 \), \( 4 \) is a coefficient, \( -9 \) is a constant, and \( x \) is the symbol representing the unknown quantity. \( 4x \) is a term, not a variable. So the variable is \( x \).

A variable is a letter representing an unknown value. In \( 5 = 9t + 3 \), \( 5 \) and \( 3 \) are constants, \( 9 \) is a coefficient, and \( t \) is the letter representing the unknown. So the variable is \( t \).

A numerical term has only numbers (no variables), a variable term has a variable, an isolated term is not part of a sum/difference in context, and a constant term is a number without a variable. \( 5x^2 \) has the variable \( x \), so it's a variable term.

Answer:

c. \( x \)

Second Question: What is the variable in the equation \( 5 = 9t + 3 \)?