Multiple choice Which of the following expressions is not a linear expression? 7x + 2 $\frac{4}{\sqrt 3}$x – y $\sqrt 7$y + x – 3 3xy + 7 Reveal answer Fill a bubble to check yourself D Correct answer Explanation The expression having a degree one is called a linear expression. Therefore, 3xy + 7 is not a linear expression because its degree is 2.