Given: Different expressions as shown in the options
To Determine: Which of the expression cannot be part of a rational expression
Solution
A rational expression is simply a quotient of two polynomials. Or in other words, it is a fraction whose numerator and denominator are polynomials. e.g.
An irrational algebraic expression is one that is not rational
Hence, the expression that is not part of a rational expression is
3x² - 4√x