Question

Which of the following is an expression in one variable?

• A. $2x+3y$
• B. $x^2+2x+3$
• C. $x^2+2y$
• D. $5$

Answer 1

The correct option is B $x^2+2x+3$

The expressions 2x + 3y and $x^2+2y$, both have two variables, x and y.

The expression $x^2+2x+3$ has one variable, which is x. Hence, it is an expression in one variable. The degree of this expression, or the highest exponent on x, is 2.

The expression 5 is a constant. It has no variables.