
Which of the following is not a linear equation in one variable? 
a) 33 
b) 33(x+y) 
c) 33x 
d) 33y

- Option b) 33 (x + y) is not a linear equation in 1 variable.
 - Here, we can see that there are 2 variables used ⇨ x & y. Hence, even though it's a linear equation, it's not in 1 variable. 
 - All the other options are in 1 variable or don't have a variable at all.